| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1911 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1912 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1913 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1914 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1915 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1916 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1917 | ----- | z | ----- | z | ----- | z | ----- | z | 97.00 | 112.00 | 105.00 | f | 103.00 | 101.00 | 102.00 | 90.00 | a | 82.00 | a | ----- | z | |||||
| 1918 | 82.00 | d | 79.00 | a | 85.00 | b | 90.00 | a | 95.00 | 109.00 | 106.00 | 107.00 | 101.00 | 99.00 | 89.00 | 79.00 | 109.00 | h | ||||||||
| 1919 | 73.00 | 80.00 | 86.00 | 96.00 | 96.00 | a | 111.00 | 103.00 | 106.00 | 103.00 | a | 89.00 | d | 80.00 | 77.00 | 111.00 | f | |||||||||
| 1920 | 80.00 | 75.00 | 81.00 | 90.00 | 103.00 | 109.00 | 111.00 | l | 106.00 | 106.00 | d | 96.00 | k | 81.00 | a | 78.00 | e | ----- | z | |||||||
| 1921 | 79.00 | c | 92.00 | 87.00 | 96.00 | 98.00 | 108.00 | 105.00 | a | 104.00 | a | 102.00 | 100.00 | a | 85.00 | 81.00 | a | 108.00 | g | |||||||
| 1922 | 78.00 | 80.00 | 82.00 | 91.00 | 106.00 | 112.00 | 109.00 | 108.00 | 106.00 | 100.00 | a | 78.00 | a | 76.00 | 112.00 | b | ||||||||||
| 1923 | 81.00 | 82.00 | 84.00 | 90.00 | a | 103.00 | 109.00 | f | 105.00 | l | 103.00 | a | 102.00 | a | 95.00 | 80.00 | 79.00 | 109.00 | u | |||||||
| 1924 | 77.00 | d | 85.00 | g | 83.00 | a | 91.00 | f | 101.00 | j | 110.00 | e | 107.00 | i | 110.00 | k | 104.00 | f | 93.00 | s | ----- | z | ----- | z | ----- | z |
| 1925 | 78.00 | o | 88.00 | k | 97.00 | g | 101.00 | g | 104.00 | j | 105.00 | t | 109.00 | f | 105.00 | i | ----- | z | ----- | z | ----- | z | 76.00 | s | ----- | z |
| 1926 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1927 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1928 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1929 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1930 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1931 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1932 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1933 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1934 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1935 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1936 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1937 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1938 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1939 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1940 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 86.00 | a | 83.00 | ----- | z | |
| 1941 | 76.00 | 82.00 | 81.00 | 87.00 | 102.00 | 108.00 | 110.00 | 105.00 | 104.00 | 97.00 | 89.00 | 84.00 | 110.00 | |||||||||||||
| 1942 | 79.00 | 78.00 | 88.00 | 89.00 | 103.00 | 111.00 | 113.00 | 104.00 | 102.00 | 98.00 | 88.00 | 80.00 | 113.00 | |||||||||||||
| 1943 | 80.00 | 90.00 | 91.00 | 101.00 | 102.00 | 107.00 | 111.00 | 103.00 | 109.00 | 99.00 | 88.00 | a | 80.00 | c | 111.00 | d | ||||||||||
| 1944 | 80.00 | 76.00 | a | 85.00 | 88.00 | 98.00 | 110.00 | 110.00 | 113.00 | 104.00 | s | 101.00 | 85.00 | 77.00 | a | 113.00 | u | |||||||||
| 1945 | 76.00 | 80.00 | 83.00 | a | 97.00 | ----- | z | ----- | z | ----- | z | 105.00 | 110.00 | 95.00 | 91.00 | 79.00 | ----- | z | ||||||||
| 1946 | 80.00 | 82.00 | 87.00 | c | 97.00 | a | 97.00 | 108.00 | 106.00 | 105.00 | 104.00 | 87.00 | 85.00 | 86.00 | 108.00 | d | ||||||||||
| 1947 | 80.00 | 82.00 | 86.00 | 94.00 | a | 103.00 | 106.00 | 111.00 | 104.00 | 107.00 | 98.00 | 88.00 | 74.00 | a | 111.00 | b | ||||||||||
| 1948 | 84.00 | a | 85.00 | a | 80.00 | a | 100.00 | 103.00 | 108.00 | a | 110.00 | a | 107.00 | h | 110.00 | c | 98.00 | 80.00 | 78.00 | a | 110.00 | q | ||||
| 1949 | 67.00 | c | 81.00 | c | 84.00 | b | 98.00 | 102.00 | 107.00 | 109.00 | 107.00 | 107.00 | 96.00 | 89.00 | 82.00 | 109.00 | h | |||||||||
| 1950 | 82.00 | 83.00 | 91.00 | 100.00 | 98.00 | 111.00 | 110.00 | 107.00 | a | 112.00 | 103.00 | 88.00 | 85.00 | 112.00 | a | |||||||||||
| 1951 | 82.00 | 88.00 | 82.00 | 95.00 | ----- | z | 108.00 | i | 108.00 | c | 106.00 | a | 105.00 | 99.00 | 80.00 | a | 81.00 | ----- | z | |||||||
| 1952 | 75.00 | 76.00 | b | 80.00 | 93.00 | 100.00 | 107.00 | 110.00 | 107.00 | 107.00 | a | 99.00 | 88.00 | 77.00 | a | 110.00 | d | |||||||||
| 1953 | 84.00 | a | 82.00 | 90.00 | 96.00 | 98.00 | a | 108.00 | e | 110.00 | 107.00 | a | 107.00 | 103.00 | a | 90.00 | 81.00 | 110.00 | i | |||||||
| 1954 | 78.00 | a | 85.00 | a | 86.00 | 96.00 | 96.00 | 108.00 | 109.00 | 105.00 | 105.00 | 99.00 | a | 89.00 | a | 85.00 | b | 109.00 | f | |||||||
| 1955 | 75.00 | 82.00 | 85.00 | 89.00 | h | 102.00 | a | 110.00 | b | 107.00 | c | 100.00 | 105.00 | b | 103.00 | 88.00 | 82.00 | b | 110.00 | r | ||||||
| 1956 | 82.00 | a | 78.00 | b | 91.00 | a | 93.00 | a | 104.00 | 111.00 | 110.00 | c | 106.00 | b | 108.00 | a | 98.00 | a | 87.00 | d | 77.00 | b | 111.00 | r | ||
| 1957 | 77.00 | f | 91.00 | c | 89.00 | a | 90.00 | 99.00 | 115.00 | 112.00 | 109.00 | 107.00 | c | 101.00 | e | 75.00 | b | 75.00 | 115.00 | t | ||||||
| 1958 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1959 | 83.00 | 79.00 | 84.00 | b | 98.00 | 101.00 | b | 112.00 | 108.00 | b | 105.00 | d | 105.00 | b | 99.00 | b | 83.00 | c | 81.00 | d | 112.00 | u | ||||
| 1960 | 78.00 | b | 77.00 | j | 89.00 | h | 96.00 | j | 108.00 | f | 115.00 | f | 113.00 | b | 110.00 | k | 104.00 | c | 99.00 | 89.00 | c | 82.00 | ----- | z | ||
| 1961 | 77.00 | 82.00 | 87.00 | 95.00 | 100.00 | 110.00 | a | 110.00 | 110.00 | 103.00 | 98.00 | 82.00 | 78.00 | 110.00 | a | |||||||||||
| 1962 | 79.00 | 86.00 | 90.00 | 101.00 | 101.00 | 111.00 | 107.00 | 110.00 | 107.00 | 98.00 | 98.00 | e | 79.00 | b | 111.00 | g | ||||||||||
| 1963 | 79.00 | a | 88.00 | 85.00 | c | 96.00 | e | 103.00 | c | 106.00 | b | 109.00 | a | 104.00 | c | 109.00 | j | 103.00 | h | 88.00 | m | ----- | z | ----- | z | |
| 1964 | 79.00 | h | 77.00 | f | 85.00 | g | 97.00 | f | 101.00 | f | 107.00 | a | 110.00 | b | 105.00 | e | 104.00 | e | 100.00 | d | 86.00 | g | 80.00 | i | ----- | z |
| 1965 | 80.00 | i | 81.00 | g | 85.00 | f | 102.00 | g | 100.00 | j | 105.00 | i | 107.00 | i | 109.00 | j | 102.00 | i | 102.00 | l | 98.00 | h | 82.00 | e | ----- | z |
| 1966 | 77.00 | i | 73.00 | d | 87.00 | d | 98.00 | c | 100.00 | g | 108.00 | d | 109.00 | b | 105.00 | g | 105.00 | d | 92.00 | d | 90.00 | g | 79.00 | f | ----- | z |
| 1967 | 83.00 | i | 86.00 | f | 90.00 | g | 90.00 | k | 101.00 | g | 106.00 | 109.00 | h | 106.00 | d | 103.00 | c | 95.00 | e | 90.00 | h | 74.00 | ----- | z | ||
| 1968 | 75.00 | 85.00 | 87.00 | 94.00 | b | 104.00 | 113.00 | 108.00 | 104.00 | 107.00 | b | 95.00 | 84.00 | d | 80.00 | 113.00 | h | |||||||||
| 1969 | 82.00 | b | 79.00 | 95.00 | e | 98.00 | d | 101.00 | e | ----- | z | 103.00 | u | 108.00 | l | 106.00 | q | 100.00 | j | 81.00 | m | 82.00 | m | ----- | z | |
| 1970 | 80.00 | n | 84.00 | i | 85.00 | j | 98.00 | i | 106.00 | k | 112.00 | k | 109.00 | i | 107.00 | j | 108.00 | k | 89.00 | i | 87.00 | l | 80.00 | j | ----- | z |
| 1971 | 88.00 | k | 86.00 | k | 95.00 | j | 92.00 | i | 98.00 | l | 108.00 | g | 112.00 | h | 102.00 | i | 107.00 | k | 100.00 | n | 89.00 | j | 80.00 | k | ----- | z |
| 1972 | 77.00 | j | 86.00 | j | 95.00 | j | 95.00 | k | 99.00 | l | 109.00 | h | 110.00 | l | 108.00 | h | 102.00 | j | 102.00 | o | 81.00 | k | 74.00 | s | ----- | z |
| 1973 | 76.00 | p | 75.00 | j | 75.00 | e | 100.00 | b | 104.00 | e | 110.00 | g | 113.00 | c | 113.00 | e | 106.00 | d | 101.00 | i | 98.00 | b | 80.00 | r | ----- | z |
| 1974 | 78.00 | g | 88.00 | a | 88.00 | n | 95.00 | j | 107.00 | 111.00 | g | 111.00 | n | 106.00 | i | 105.00 | n | 97.00 | j | 83.00 | k | 76.00 | g | ----- | z | |
| 1975 | 80.00 | g | 80.00 | f | 85.00 | h | 87.00 | 98.00 | c | 105.00 | n | 106.00 | n | 109.00 | j | 99.00 | v | ----- | z | ----- | z | ----- | z | ----- | z | |
| 1976 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1977 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1978 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1979 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1980 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1983 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1984 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1985 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1986 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1987 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1988 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1989 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1990 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1991 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1992 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1993 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1994 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1995 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1996 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1997 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1998 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 79.00 | c | ----- | z |
| 1999 | 83.00 | a | 84.00 | b | 87.00 | b | 97.00 | a | 105.00 | a | 107.00 | d | 109.00 | c | 107.00 | c | 107.00 | e | 101.00 | e | 93.00 | a | 87.00 | c | ----- | z |
| 2000 | 89.00 | b | 83.00 | e | 83.00 | f | 100.00 | b | 110.00 | e | 107.00 | b | 113.00 | f | 106.00 | i | 111.00 | e | 102.00 | l | 79.00 | k | 78.00 | g | ----- | z |
| 2001 | 76.00 | j | 80.00 | f | 88.00 | m | 99.00 | h | 105.00 | j | 109.00 | i | 116.00 | g | 109.00 | l | 108.00 | h | 98.00 | d | 90.00 | f | 81.00 | c | ----- | z |
| 2002 | 82.00 | e | 87.00 | f | 89.00 | g | 97.00 | c | 108.00 | e | 110.00 | d | 110.00 | f | 109.00 | h | 108.00 | b | 97.00 | g | 88.00 | d | 78.00 | f | ----- | z |
| 2003 | 84.00 | i | 85.00 | d | 88.00 | f | 92.00 | g | 107.00 | c | 109.00 | e | 111.00 | h | 109.00 | g | 107.00 | h | 103.00 | j | 84.00 | i | 81.00 | d | ----- | z |
| 2004 | 79.00 | h | 85.00 | e | 97.00 | h | 97.00 | j | 99.00 | f | 106.00 | b | 106.00 | i | 105.00 | k | 105.00 | m | 99.00 | i | 86.00 | f | 81.00 | h | ----- | z |
| 2005 | 82.00 | p | 72.00 | b | 87.00 | e | 93.00 | h | 107.00 | e | 110.00 | h | 112.00 | e | 109.00 | e | 106.00 | f | 99.00 | f | 90.00 | c | 81.00 | c | ----- | z |
| 2006 | 82.00 | a | 85.00 | 85.00 | d | 94.00 | c | 105.00 | d | 113.00 | d | 113.00 | f | 107.00 | d | 100.00 | g | 101.00 | e | 93.00 | c | 81.00 | f | ----- | z | |
| 2007 | 83.00 | c | 85.00 | c | 99.00 | c | 94.00 | d | 103.00 | g | 113.00 | f | 115.00 | c | 108.00 | b | 108.00 | d | 98.00 | e | 95.00 | a | 80.00 | c | ----- | z |
| 2008 | 77.00 | e | 79.00 | k | 90.00 | 98.00 | b | 104.00 | i | 109.00 | q | 109.00 | x | 109.00 | i | 102.00 | v | 99.00 | m | 93.00 | a | 79.00 | ----- | z | ||
| 2009 | 83.00 | b | 92.00 | b | 90.00 | 99.00 | 104.00 | d | 105.00 | 110.00 | a | 110.00 | 103.00 | a | 100.00 | 96.00 | a | 67.00 | x | ----- | z | |||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 79.51 | 82.56 | 86.18 | 95.08 | 101.84 | 109.08 | 109.45 | 106.33 | 105.70 | 98.14 | 87.34 | 80.05 | 110.78 | |||||||||||||
| S.D. | 3.86 | 4.87 | 4.40 | 4.01 | 3.68 | 2.37 | 2.46 | 2.75 | 2.76 | 3.50 | 5.40 | 3.05 | 1.48 | |||||||||||||
| SKEW | -0.66 | -0.03 | 0.31 | -0.48 | 0.06 | 0.41 | -0.28 | 0.48 | 0.25 | -1.34 | -0.11 | 0.13 | -0.33 | |||||||||||||
| MAX | 89.00 | 92.00 | 99.00 | 101.00 | 110.00 | 115.00 | 115.00 | 113.00 | 112.00 | 103.00 | 98.00 | 87.00 | 113.00 | |||||||||||||
| MIN | 67.00 | 72.00 | 75.00 | 87.00 | 95.00 | 105.00 | 103.00 | 100.00 | 101.00 | 87.00 | 75.00 | 74.00 | 108.00 | |||||||||||||
| YRS | 37 | 39 | 38 | 38 | 38 | 37 | 33 | 36 | 37 | 36 | 38 | 39 | 9 | |||||||||||||