| YEAR(S) | JAN | FEB | MAR | APR | MAY | JUN | JUL | AUG | SEP | OCT | NOV | DEC | ANN | |||||||||||||
| 1961 | ----- | z | ----- | z | ----- | z | 79.64 | a | 84.66 | 100.13 | 104.71 | 100.27 | 88.35 | 76.11 | 59.72 | 50.40 | 82.67 | |||||||||
| 1962 | 53.89 | 59.34 | 63.63 | 82.22 | 83.60 | 95.72 | 100.66 | 100.39 | 93.03 | 79.90 | 64.87 | 52.63 | 77.49 | |||||||||||||
| 1963 | 48.53 | 66.54 | 66.29 | 72.48 | 87.81 | 91.03 | 101.16 | 98.82 | 90.75 | 81.31 | 63.43 | 51.27 | 76.62 | |||||||||||||
| 1964 | 50.77 | 58.19 | 64.92 | 75.13 | 83.89 | 93.18 | 101.95 | 99.95 | a | 90.68 | 82.73 | 58.85 | 54.73 | 76.25 | ||||||||||||
| 1965 | 55.65 | 61.11 | 66.66 | 72.57 | 83.29 | 90.70 | 98.50 | 98.19 | 85.40 | 78.63 | 62.67 | 48.97 | a | 75.19 | ||||||||||||
| 1966 | 49.08 | 54.76 | a | 66.81 | 78.77 | 88.48 | 94.95 | 100.00 | 100.60 | 90.82 | b | 76.20 | c | 63.45 | 53.93 | a | 76.49 | |||||||||
| 1967 | 53.06 | 61.70 | 70.27 | a | 65.82 | b | 84.65 | 90.72 | 103.08 | 103.06 | 91.25 | 78.24 | 65.17 | 49.95 | 76.41 | |||||||||||
| 1968 | 51.44 | 63.53 | 68.74 | 74.93 | 85.68 | 97.05 | 101.11 | 96.13 | 91.80 | 78.29 | 65.58 | 47.94 | 76.85 | |||||||||||||
| 1969 | 54.94 | 55.84 | 64.52 | 76.97 | 88.69 | 92.25 | 101.79 | 103.39 | 93.85 | 73.89 | 63.70 | 52.80 | a | 76.88 | ||||||||||||
| 1970 | 52.24 | 61.45 | 67.08 | 71.55 | 87.26 | 95.85 | 103.45 | 103.21 | 89.18 | 75.18 | 63.30 | 51.97 | 76.81 | |||||||||||||
| 1971 | 52.73 | 60.61 | 66.89 | 75.03 | 81.87 | 94.37 | 103.76 | 104.53 | 91.15 | 73.98 | 61.12 | 51.56 | 76.47 | |||||||||||||
| 1972 | 49.89 | 59.19 | 75.02 | 76.47 | 86.61 | 95.40 | 103.68 | 98.58 | 88.67 | 74.63 | 59.78 | 49.29 | 76.43 | |||||||||||||
| 1973 | 49.98 | 60.13 | a | 63.37 | 74.95 | 89.48 | 97.77 | 102.92 | 100.06 | 89.62 | 77.03 | 60.88 | 53.56 | 76.65 | ||||||||||||
| 1974 | 50.68 | 59.00 | 69.65 | 75.70 | 88.37 | 98.52 | 101.32 | 97.92 | 95.35 | 78.45 | 62.12 | 52.15 | 77.43 | |||||||||||||
| 1975 | 51.66 | 60.04 | 65.97 | 70.10 | 84.90 | 95.65 | 101.08 | 97.90 | 92.42 | 76.74 | 61.52 | 56.03 | 76.17 | |||||||||||||
| 1976 | 54.73 | 60.47 | 65.92 | 73.95 | 88.24 | 94.03 | 100.98 | 94.37 | 88.40 | 77.27 | 64.15 | 48.92 | 75.95 | |||||||||||||
| 1977 | 52.50 | 63.05 | 64.02 | 80.03 | 77.69 | 98.72 | 101.97 | 98.98 | 89.12 | 79.02 | 62.25 | 56.21 | 76.96 | |||||||||||||
| 1978 | 55.27 | 60.09 | 69.48 | 72.35 | d | 83.00 | 96.12 | 101.02 | 99.79 | 88.28 | 81.48 | 62.47 | 48.52 | 76.49 | ||||||||||||
| 1979 | 50.47 | 56.27 | 67.43 | a | 75.37 | c | 86.66 | 93.47 | 99.77 | 95.24 | 94.17 | 79.10 | 60.40 | 53.16 | 75.96 | |||||||||||
| 1980 | 57.85 | 62.18 | a | 64.95 | 75.45 | 80.55 | 91.65 | 101.63 | 99.24 | 90.03 | 77.95 | 61.93 | 56.16 | 76.63 | ||||||||||||
| 1981 | 56.92 | 61.57 | 67.76 | 80.08 | 86.47 | 99.27 | 102.32 | 100.32 | 92.87 | 74.45 | 65.50 | 53.60 | 78.43 | |||||||||||||
| 1982 | 51.63 | 59.02 | 64.15 | 74.42 | 85.94 | 91.83 | 96.76 | 97.85 | 86.97 | 72.66 | 58.50 | 51.65 | a | 74.28 | ||||||||||||
| 1983 | 52.11 | 58.52 | 64.87 | 69.57 | 83.21 | 93.02 | 96.98 | 94.60 | 92.47 | 77.53 | 64.17 | 52.76 | 74.98 | |||||||||||||
| 1984 | 55.45 | 59.03 | 67.85 | 73.33 | 89.85 | 93.10 | 99.44 | 96.66 | 92.02 | 71.40 | 59.81 | c | 48.89 | 75.57 | ||||||||||||
| 1985 | 51.31 | 56.23 | 64.71 | 78.43 | a | 85.84 | 97.35 | 102.31 | 97.40 | 84.45 | 75.23 | 58.32 | 51.90 | 75.29 | ||||||||||||
| 1986 | 55.77 | 61.15 | e | 72.32 | 76.21 | a | 87.12 | b | 97.25 | b | 97.45 | 101.98 | 85.50 | 72.86 | f | 65.67 | a | 51.89 | 77.48 | |||||||
| 1987 | 51.79 | 62.28 | a | 65.53 | 79.35 | 84.95 | 95.40 | 96.37 | 99.50 | 91.95 | 81.05 | 63.40 | 48.68 | 76.69 | ||||||||||||
| 1988 | 49.73 | 60.88 | 69.08 | 73.87 | 83.13 | a | 92.62 | 103.32 | 98.73 | 89.57 | 82.92 | 63.75 | 52.87 | 76.70 | ||||||||||||
| 1989 | 50.52 | 57.75 | 70.98 | 83.43 | 85.19 | 95.57 | a | 102.65 | 97.35 | 88.62 | 75.53 | 63.05 | 51.16 | 76.82 | ||||||||||||
| 1990 | 51.66 | 57.05 | 69.89 | 79.38 | 84.29 | 95.25 | 102.24 | 98.37 | 92.08 | 75.27 | 58.32 | 43.27 | 75.59 | |||||||||||||
| 1991 | 48.21 | 62.61 | 61.97 | 73.18 | 79.95 | 90.43 | 99.55 | a | 98.10 | 92.67 | 81.79 | 62.73 | 52.34 | 75.29 | ||||||||||||
| 1992 | 50.48 | 60.78 | 67.19 | 80.05 | 90.68 | 93.80 | 97.58 | 100.73 | 90.90 | 80.16 | 60.30 | 48.63 | 76.77 | |||||||||||||
| 1993 | 49.19 | 57.30 | 68.08 | 77.50 | 87.19 | 91.03 | 99.00 | 98.71 | 89.68 | 77.97 | 59.08 | 51.73 | 75.54 | |||||||||||||
| 1994 | 52.92 | 55.61 | 72.53 | 77.57 | 85.15 | 98.21 | a | 104.39 | 102.68 | 90.68 | 75.05 | 56.28 | 51.05 | 76.84 | ||||||||||||
| 1995 | 52.81 | 64.45 | 66.89 | 73.23 | 80.00 | 90.08 | 100.76 | 101.48 | 93.30 | 77.08 | 66.23 | 54.26 | 76.71 | |||||||||||||
| 1996 | 54.89 | 62.67 | 68.60 | 78.58 | 86.95 | 96.90 | 104.11 | 100.31 | 89.00 | 74.48 | 60.73 | 51.52 | 77.40 | |||||||||||||
| 1997 | 54.21 | 60.00 | 69.26 | 75.05 | 90.73 | 93.22 | 97.32 | 99.79 | 89.98 | 73.69 | 60.98 | 49.67 | a | 76.16 | ||||||||||||
| 1998 | 51.69 | 54.34 | 63.73 | 69.28 | 76.42 | 87.57 | 101.16 | 100.11 | 88.53 | 72.71 | 60.82 | 53.24 | b | 73.30 | ||||||||||||
| 1999 | 54.90 | 59.04 | 68.63 | 70.19 | a | 84.65 | 93.93 | 99.21 | 98.89 | 90.77 | 78.05 | 62.78 | 54.10 | 76.26 | ||||||||||||
| 2000 | 54.65 | 61.41 | 68.45 | a | 79.87 | 88.79 | 98.23 | 101.00 | 99.85 | 88.64 | a | 75.88 | a | 57.33 | 51.95 | 77.17 | ||||||||||
| 2001 | 50.08 | 54.54 | 69.40 | b | 74.88 | e | 92.38 | a | 98.70 | 100.71 | 103.44 | 93.70 | 80.05 | 65.73 | 52.35 | a | 78.00 | |||||||||
| 2002 | 52.39 | 58.82 | 65.45 | 78.48 | 85.85 | 99.18 | 106.26 | 98.66 | 91.85 | 75.34 | 64.60 | 53.18 | 77.51 | |||||||||||||
| 2003 | 58.47 | 59.12 | 68.48 | a | 72.67 | 86.34 | 98.23 | 105.37 | a | 101.23 | 94.87 | 83.18 | 58.52 | 49.73 | 78.02 | |||||||||||
| 2004 | 51.84 | 57.09 | 74.68 | 78.55 | 87.13 | 97.08 | 102.45 | 99.58 | a | 90.42 | 76.21 | 61.77 | 53.85 | 77.55 | ||||||||||||
| 2005 | 56.26 | 60.50 | 68.06 | 74.43 | 88.05 | 94.07 | 106.73 | 101.26 | 88.27 | 78.05 | 65.35 | 52.08 | 77.76 | |||||||||||||
| 2006 | 55.31 | 61.41 | 64.40 | a | 75.08 | 90.84 | 100.05 | 107.00 | a | 100.19 | 90.93 | 76.00 | 64.58 | 51.11 | 78.08 | |||||||||||
| 2007 | 52.23 | 61.43 | 73.23 | a | 79.30 | 90.31 | 98.81 | a | 106.13 | 103.27 | 91.38 | 76.90 | 67.03 | 50.37 | 79.20 | |||||||||||
| 2008 | 53.35 | 59.40 | 69.50 | 77.58 | 85.68 | 97.70 | 105.19 | 104.39 | 93.98 | 78.08 | 67.40 | 52.68 | 78.74 | |||||||||||||
| 2009 | 56.60 | a | 57.41 | 66.94 | 75.50 | 92.16 | 91.52 | 105.19 | 98.47 | 94.83 | 73.69 | 61.63 | 50.00 | 77.00 | ||||||||||||
| 2010 | 51.58 | 59.59 | 67.32 | 73.20 | 81.77 | 97.62 | 105.66 | 100.44 | 91.55 | 79.35 | 63.07 | 54.18 | 77.11 | |||||||||||||
| 2011 | 51.73 | 57.70 | 67.87 | 76.43 | 82.10 | 95.32 | 101.34 | 101.74 | 94.45 | 79.44 | 60.40 | 52.48 | 76.75 | |||||||||||||
| 2012 | 53.85 | 62.12 | 67.56 | 78.55 | 90.32 | 98.57 | 102.66 | 104.29 | 96.25 | 79.68 | 65.20 | 56.47 | 79.63 | |||||||||||||
| 2013 | 52.89 | 60.64 | 72.85 | 78.50 | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | ----- | z | 54.50 | z | 62.13 | ||||
| Period of Record Statistics | ||||||||||||||||||||||||||
| MEAN | 52.75 | 59.71 | 67.69 | 75.71 | 85.86 | 95.16 | 101.79 | 99.83 | 90.87 | 77.35 | 62.32 | 51.80 | 76.71 | |||||||||||||
| S.D. | 2.43 | 2.57 | 2.92 | 3.51 | 3.50 | 3.03 | 2.68 | 2.39 | 2.57 | 2.82 | 2.63 | 2.43 | 1.15 | |||||||||||||
| SKEW | 0.31 | -0.06 | 0.53 | -0.31 | -0.45 | -0.30 | -0.08 | -0.02 | -0.25 | 0.15 | -0.18 | -0.63 | -0.04 | |||||||||||||
| MAX | 58.47 | 66.54 | 75.02 | 83.43 | 92.38 | 100.13 | 107.00 | 104.53 | 96.25 | 83.18 | 67.40 | 56.47 | 79.63 | |||||||||||||
| MIN | 48.21 | 54.34 | 61.97 | 65.82 | 76.42 | 87.57 | 96.37 | 94.37 | 84.45 | 71.40 | 56.28 | 43.27 | 73.30 | |||||||||||||
| NO YRS | 52 | 52 | 52 | 52 | 52 | 52 | 52 | 52 | 52 | 51 | 52 | 52 | 50 | |||||||||||||