| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1951 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1952 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1953 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1954 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1955 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1956 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1957 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1958 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1959 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1960 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1961 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1962 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1963 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1964 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1965 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1966 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1967 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1968 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1969 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1970 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1971 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1972 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1973 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1974 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1975 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | 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 | 106.00 | b | 101.00 | d | 89.00 | e | 80.00 | d | 65.00 | f | ----- | z |
| 1986 | 74.00 | c | 83.00 | f | 83.00 | b | 85.00 | f | 98.00 | e | 104.00 | c | 110.00 | e | 104.00 | f | 100.00 | f | 83.00 | e | 75.00 | i | 69.00 | g | ----- | z |
| 1987 | 66.00 | i | 67.00 | h | 71.00 | g | 90.00 | e | 92.00 | l | 104.00 | g | 107.00 | k | 107.00 | k | 102.00 | h | 94.00 | g | 74.00 | g | 65.00 | g | ----- | z |
| 1988 | 63.00 | e | 75.00 | a | 80.00 | a | 85.00 | e | 94.00 | b | 104.00 | 107.00 | 102.00 | d | 101.00 | d | 94.00 | g | 83.00 | d | 70.00 | j | ----- | z | ||
| 1989 | 63.00 | c | 76.00 | c | 79.00 | c | 93.00 | a | 95.00 | a | 104.00 | a | 112.00 | 105.00 | e | 97.00 | h | 89.00 | c | 80.00 | b | 71.00 | b | ----- | z | |
| 1990 | 73.00 | 73.00 | 82.00 | 87.00 | a | 90.00 | 105.00 | b | 106.00 | 104.00 | a | 101.00 | a | 88.00 | b | 80.00 | a | 64.00 | 106.00 | h | ||||||
| 1991 | 62.00 | 74.00 | 67.00 | 80.00 | 91.00 | a | 97.00 | 107.00 | 102.00 | 100.00 | a | 93.00 | 80.00 | a | 62.00 | 107.00 | c | |||||||||
| 1992 | 62.00 | 72.00 | 71.00 | 91.00 | a | 98.00 | d | 98.00 | b | 103.00 | d | 106.00 | c | 96.00 | d | 94.00 | 72.00 | a | 60.00 | 106.00 | s | |||||
| 1993 | 61.00 | 58.00 | 77.00 | 83.00 | a | 92.00 | 101.00 | 102.00 | 105.00 | d | 101.00 | b | 93.00 | a | 74.00 | 67.00 | 105.00 | h | ||||||||
| 1994 | 71.00 | c | 69.00 | 80.00 | 90.00 | b | 95.00 | 107.00 | a | 108.00 | 106.00 | 97.00 | b | 83.00 | d | 74.00 | a | 63.00 | 108.00 | m | ||||||
| 1995 | 58.00 | 78.00 | 74.00 | 80.00 | 86.00 | d | 100.00 | b | 108.00 | c | 105.00 | c | 102.00 | 88.00 | 79.00 | 71.00 | 108.00 | l | ||||||||
| 1996 | 67.00 | 78.00 | 81.00 | 91.00 | a | 100.00 | 104.00 | 109.00 | 106.00 | 104.00 | 97.00 | 77.00 | 65.00 | 109.00 | a | |||||||||||
| 1997 | 65.00 | 69.00 | b | 83.00 | 84.00 | 99.00 | a | 100.00 | 105.00 | c | 104.00 | a | 96.00 | 88.00 | 81.00 | a | 63.00 | 105.00 | h | |||||||
| 1998 | 68.00 | 58.00 | 79.00 | 85.00 | 85.00 | c | 101.00 | f | 111.00 | b | 103.00 | c | 96.00 | 83.00 | 71.00 | a | 68.00 | 111.00 | o | |||||||
| 1999 | 66.00 | 70.00 | a | 75.00 | a | 85.00 | 91.00 | a | 103.00 | 106.00 | 100.00 | 98.00 | 92.00 | 86.00 | 67.00 | a | 106.00 | d | ||||||||
| 2000 | ----- | z | 69.00 | b | 78.00 | 91.00 | 101.00 | a | 102.00 | 106.00 | a | 106.00 | e | 98.00 | d | 92.00 | d | 65.00 | a | 66.00 | ----- | z | ||||
| 2001 | 64.00 | c | 71.00 | a | 79.00 | 87.00 | 101.00 | 101.00 | 109.00 | a | 109.00 | 96.00 | 95.00 | 75.00 | 59.00 | 109.00 | e | |||||||||
| 2002 | 64.00 | 73.00 | 82.00 | 91.00 | 102.00 | a | 103.00 | 113.00 | a | 107.00 | 100.00 | d | 85.00 | l | 74.00 | a | 62.00 | 113.00 | s | |||||||
| 2003 | 73.00 | 76.00 | 76.00 | 80.00 | 105.00 | 103.00 | e | 109.00 | c | 103.00 | d | 100.00 | 93.00 | 67.00 | 65.00 | b | 109.00 | n | ||||||||
| 2004 | 64.00 | 64.00 | 88.00 | 88.00 | 92.00 | 101.00 | 103.00 | a | 106.00 | 100.00 | 87.00 | b | 73.00 | a | 66.00 | b | 106.00 | f | ||||||||
| 2005 | 70.00 | c | 61.00 | a | 80.00 | c | 80.00 | c | 96.00 | c | 100.00 | b | 111.00 | b | 100.00 | a | 94.00 | 87.00 | a | 73.00 | 68.00 | 111.00 | s | |||
| 2006 | 66.00 | a | 71.00 | 70.00 | 83.00 | 96.00 | a | 106.00 | a | 108.00 | c | 99.00 | d | 97.00 | d | 88.00 | h | 78.00 | h | 65.00 | c | ----- | z | |||
| 2007 | 63.00 | 70.00 | 86.00 | 89.00 | 92.00 | a | 103.00 | c | 111.00 | c | 102.00 | e | 101.00 | 83.00 | g | 80.00 | i | 66.00 | a | ----- | z | |||||
| 2008 | ----- | z | 69.00 | 76.00 | 88.00 | 104.00 | d | 105.00 | a | 108.00 | a | 105.00 | 99.00 | 91.00 | a | 79.00 | ----- | z | ----- | z | ||||||
| 2009 | 65.00 | a | 68.00 | 80.00 | 90.00 | 100.00 | d | 105.00 | a | 111.00 | 109.00 | 102.00 | 86.00 | 81.00 | 61.00 | 111.00 | f | |||||||||
| 2010 | 63.00 | 66.00 | 75.00 | 84.00 | i | 88.00 | 107.00 | 109.00 | 105.00 | 101.00 | 92.00 | 79.00 | 65.00 | 109.00 | i | |||||||||||
| 2011 | 70.00 | a | 65.00 | a | 76.00 | 86.00 | 89.00 | 105.00 | 106.00 | 107.00 | 102.00 | a | 93.00 | c | 75.00 | d | 65.00 | 107.00 | j | |||||||
| 2012 | 65.00 | e | 67.00 | 78.00 | a | 96.00 | b | 100.00 | b | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 72.00 | h | 67.00 | s | ----- | z | |
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 65.83 | 69.60 | 78.27 | 86.92 | 95.38 | 102.83 | 107.92 | 104.48 | 99.29 | 89.82 | 76.43 | 64.95 | 107.33 | |||||||||||||
| S.D. | 4.15 | 5.49 | 4.70 | 4.40 | 5.51 | 2.65 | 2.87 | 2.60 | 2.54 | 3.98 | 5.05 | 3.12 | 1.53 | |||||||||||||
| SKEW | 0.47 | -0.53 | -0.32 | -0.07 | -0.12 | -0.42 | -0.31 | -0.38 | -0.33 | -0.25 | -0.41 | 0.09 | 0.38 | |||||||||||||
| MAX | 74.00 | 78.00 | 88.00 | 96.00 | 105.00 | 107.00 | 113.00 | 109.00 | 104.00 | 97.00 | 86.00 | 71.00 | 109.00 | |||||||||||||
| MIN | 58.00 | 58.00 | 67.00 | 80.00 | 85.00 | 97.00 | 102.00 | 99.00 | 94.00 | 83.00 | 65.00 | 59.00 | 106.00 | |||||||||||||
| YRS | 24 | 25 | 26 | 25 | 26 | 24 | 25 | 25 | 24 | 22 | 23 | 22 | 3 | |||||||||||||