| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1953 | 70.52 | 70.75 | 71.55 | 73.47 | 76.48 | 80.30 | 83.81 | 82.94 | 81.73 | 79.10 | 77.47 | 71.17 | a | 76.61 | ||||||||||||
| 1954 | 68.90 | 68.43 | 67.90 | 69.00 | 73.33 | a | 79.67 | 81.13 | 82.24 | b | 81.00 | 80.00 | a | 75.53 | 72.29 | 74.95 | ||||||||||
| 1955 | 69.68 | 68.54 | 67.52 | 70.67 | 76.84 | 81.53 | 82.03 | 81.65 | 81.70 | 78.50 | a | 74.03 | 70.90 | 75.30 | ||||||||||||
| 1956 | 67.43 | j | 68.59 | 68.90 | 70.80 | 73.45 | 80.03 | 80.10 | 81.35 | 83.20 | 79.06 | 73.80 | 70.26 | 75.41 | a | |||||||||||
| 1957 | 65.90 | j | 68.00 | 69.77 | 70.40 | 74.39 | 80.43 | 82.10 | j | 81.84 | 81.00 | 74.58 | 71.63 | 71.32 | 74.34 | b | ||||||||||
| 1958 | 69.23 | 68.04 | b | 68.00 | 71.17 | a | 74.00 | 76.80 | 78.87 | 81.52 | j | 81.90 | j | 77.81 | 73.17 | 70.29 | 72.74 | b | ||||||||
| 1959 | 65.68 | 67.32 | 71.00 | 68.30 | 72.77 | 78.50 | 81.42 | 82.35 | 81.83 | 76.74 | 73.17 | 71.61 | 74.23 | |||||||||||||
| 1960 | 70.81 | j | 67.00 | 68.52 | 70.47 | 74.83 | a | 81.23 | 81.37 | a | 82.59 | i | 82.00 | 76.45 | 74.27 | 70.71 | 74.68 | b | ||||||||
| 1961 | 68.81 | 70.54 | 69.65 | 66.03 | 70.81 | 77.77 | 80.26 | 81.29 | 82.30 | 78.23 | 75.60 | 72.74 | 74.50 | |||||||||||||
| 1962 | 68.16 | 68.32 | 68.74 | 68.70 | 72.16 | 75.83 | 79.90 | 82.65 | 82.93 | 79.10 | 76.28 | a | 71.87 | 74.55 | ||||||||||||
| 1963 | 69.68 | 67.96 | 69.42 | 69.93 | 74.87 | 79.77 | 80.13 | 81.48 | 83.37 | 81.48 | 78.03 | 71.42 | 75.63 | |||||||||||||
| 1964 | 72.48 | 72.48 | 70.68 | 69.23 | 75.26 | 78.90 | 80.84 | 81.52 | 82.73 | 80.26 | 75.63 | 69.74 | 75.81 | |||||||||||||
| 1965 | 66.68 | 68.43 | 68.26 | 69.08 | d | 70.96 | f | 77.67 | 79.74 | 81.13 | 81.05 | j | 79.33 | j | 75.45 | h | 70.41 | b | 72.67 | d | ||||||
| 1966 | 70.71 | 67.93 | 71.71 | 72.07 | 72.10 | 78.65 | j | 80.81 | 82.42 | 83.20 | 78.19 | 74.30 | 71.86 | j | 75.34 | b | ||||||||||
| 1967 | 72.29 | 68.39 | 66.45 | 71.57 | 72.84 | 77.90 | 80.26 | 82.52 | 84.03 | 81.45 | 78.30 | 72.33 | a | 75.69 | ||||||||||||
| 1968 | 68.16 | 66.59 | 66.84 | 68.40 | 74.16 | 79.17 | 82.42 | 83.58 | 82.37 | 76.71 | 71.37 | 70.74 | 74.21 | |||||||||||||
| 1969 | 66.42 | 68.54 | 69.68 | 73.60 | 78.81 | 79.43 | 82.94 | 82.10 | 81.80 | 78.90 | 74.23 | 73.00 | b | 75.79 | ||||||||||||
| 1970 | 69.58 | 69.68 | ----- | z | 74.07 | 75.16 | 82.83 | 82.65 | 83.32 | 81.27 | 77.94 | 75.40 | 75.13 | 77.00 | a | |||||||||||
| 1971 | 68.42 | 71.93 | ----- | z | 75.80 | 78.42 | 79.77 | 81.84 | 83.26 | 83.47 | ----- | z | 76.20 | 69.55 | 76.86 | b | ||||||||||
| 1972 | 68.35 | 68.79 | 67.35 | 69.80 | 74.58 | 79.00 | 80.90 | 82.13 | 81.80 | 77.00 | 75.67 | 71.00 | 74.70 | |||||||||||||
| 1973 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1974 | 72.67 | m | 75.95 | g | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 84.84 | l | 83.71 | b | ----- | z | ----- | z | ----- | z | 83.71 | k |
| 1975 | ----- | z | 71.92 | d | 72.87 | p | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 78.37 | ----- | z | 75.14 | j | |
| 1976 | 69.80 | u | ----- | z | 71.39 | 72.67 | u | ----- | z | ----- | z | 82.12 | n | ----- | z | 84.37 | ----- | z | 77.33 | x | ----- | z | 77.88 | j | ||
| 1977 | 69.00 | ----- | z | 69.03 | 72.27 | 76.65 | 82.40 | 82.13 | 82.97 | 82.70 | 80.55 | 74.07 | 70.52 | 76.57 | a | |||||||||||
| 1978 | ----- | z | 70.21 | 70.55 | 72.07 | 74.74 | 82.10 | 84.55 | ----- | z | 86.17 | 82.77 | 77.33 | ----- | z | 77.83 | c | |||||||||
| 1979 | 72.23 | 71.32 | 73.23 | ----- | z | 77.23 | 81.33 | ----- | z | ----- | z | 86.77 | 84.42 | 76.87 | ----- | z | 77.92 | d | ||||||||
| 1980 | ----- | z | ----- | z | 72.97 | 74.30 | 77.58 | 82.07 | 85.45 | 85.33 | a | 85.57 | 83.68 | 78.33 | 72.58 | 79.79 | b | |||||||||
| 1981 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z |
| 1982 | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 80.58 | s | 78.20 | 73.52 | 75.86 | j | ||
| 1983 | 70.13 | 70.00 | 70.13 | a | 71.87 | 76.58 | 84.23 | 86.39 | 84.39 | 86.42 | f | 84.97 | 80.69 | d | 74.35 | 77.61 | a | |||||||||
| 1984 | 72.65 | 73.71 | a | 73.94 | 78.27 | ----- | z | 87.23 | 88.19 | 88.48 | 86.17 | 82.13 | 81.25 | n | 71.03 | 80.18 | b | |||||||||
| 1985 | ----- | z | ----- | z | 72.03 | 74.53 | 79.48 | 84.37 | 84.29 | 86.03 | 85.77 | ----- | z | 75.47 | 73.94 | 79.55 | c | |||||||||
| 1986 | 72.45 | 69.57 | 70.84 | 72.37 | 72.52 | 81.77 | 84.29 | 84.87 | 84.67 | 82.90 | 77.97 | 74.97 | 77.43 | |||||||||||||
| 1987 | 71.71 | 70.46 | 72.26 | ----- | z | 76.55 | 81.27 | 86.45 | 88.61 | 85.47 | 81.74 | 78.20 | 73.90 | 78.78 | a | |||||||||||
| 1988 | 71.97 | 71.28 | 73.48 | 74.67 | ----- | z | 84.80 | ----- | z | 86.23 | ----- | z | 83.84 | ----- | z | 75.71 | 77.75 | d | ||||||||
| 1989 | 73.81 | 69.93 | 71.39 | ----- | z | 77.45 | 82.13 | 84.68 | 86.03 | 85.10 | 80.65 | 75.00 | 73.74 | 78.17 | a | |||||||||||
| 1990 | 71.42 | 69.18 | 72.16 | 71.20 | 76.42 | 81.63 | 84.10 | b | ----- | z | 86.47 | 82.23 | 75.93 | ----- | z | 77.07 | b | |||||||||
| 1991 | 70.74 | 68.71 | 71.81 | 75.53 | 77.81 | 81.47 | ----- | z | 86.80 | a | 86.27 | ----- | z | ----- | z | ----- | z | 77.39 | d | |||||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 69.99 | 69.44 | 70.22 | 71.65 | 75.28 | 80.73 | 82.48 | 83.55 | 83.58 | 80.05 | 75.82 | 72.09 | 75.34 | |||||||||||||
| S.D. | 2.09 | 1.70 | 2.03 | 2.68 | 2.21 | 2.45 | 2.34 | 2.17 | 1.81 | 2.67 | 2.16 | 1.71 | 0.96 | |||||||||||||
| SKEW | -0.19 | 0.61 | -0.04 | 0.32 | -0.04 | 0.38 | 0.62 | 0.96 | 0.32 | 0.05 | -0.04 | 0.50 | 0.72 | |||||||||||||
| MAX | 73.81 | 73.71 | 73.94 | 78.27 | 79.48 | 87.23 | 88.19 | 88.61 | 86.77 | 84.97 | 80.69 | 75.71 | 77.43 | |||||||||||||
| MIN | 65.68 | 66.59 | 66.45 | 66.03 | 70.81 | 75.83 | 78.87 | 81.13 | 81.00 | 74.58 | 71.37 | 69.55 | 74.21 | |||||||||||||
| YRS | 27 | 31 | 32 | 30 | 30 | 32 | 29 | 28 | 31 | 29 | 31 | 29 | 13 | |||||||||||||