Year Jan Feb March April May June July Aug Sept Oct Nov Dec
1936 ——- ——- ——— ——— ——— ——— ——- ——- ———– 31.36 31.65 31.54
1937 31.66 31.76 31.55 31.36 31.26 31.10 30.94 31.13 31.18 31.29 30.88 30.82
1938 30.60 30.70 30.80 31.21 31.11 31.18 30.87 31.34 31.24 31.65 31.54 31.41
1939 31.07 31.18 31.44 31.53 31.31 31.05 31.03 30.78 31.34 31.77 —— – 30.93
1940 30.76 30.78 30.60 30.92 30.65 30.60 —— —– —– ——- ——- ——- ——-
1941 —— —— —— —— —— 31.49 31.50 31.25 31.49 31.62 31.45 31.31 30.97
1942 31.18 31.00 31.44 31.58 31.56 31.62 31.25 31.11 31.32 31.80 31.73 31.46
1943 31.43 31.33 31.69 31.28 31.53 31.51 31.34 31.12 31.20 31.46 31.53 31.60
1944 31.60 31.57 31.80 31.91 31.80 32.10 31.81 31.89 31.77 31.68 31.70 31.49
1945 31.37 31.21 31.51 31.58 31.78 31.65 31.60 31.54 31.67 31.82 31.88 31.56
1946 31.12 31.30 31.19 31.43 31.39 31.06 30.76 30.95 31.44 31.54 31.80 31.26
1947 31.69 31.24 31.53 31.72 31.63 31.28 31.43 31.08 31.48 31.66 31.24 31.34
1948 31.07 31.42 31.40 31.53 31.32 30.83 30.46 31.13 31.12 31.19 31.45 31.03
1949 31.40 31.56 31.34 31.59 31.37 31.29 31.88 31.61 31.45 31.60 31.50 31.08
1950 31.14 31.12 30.79 31.01 31.34 31.31 30.95 31.06 31.20 31.05 30.91 30.34
1951 30.21 30.22 30.69 31.34 31.54 31.13 31.37 31.27 31.61 31.67 31.53 31.20
1952 31.39 31.00 31.33 31.60 31.65 31.30 31.12 31.47 31.48 31.44 31.79 31.58
1953 30.79 30.52 31.38 31.45 31.44 31.21 31.20 31.00 31.14 31.37 31.26 30.63
1954 30.47 30.56 30.76 31.06 31.41 31.41 30.74 30.76 30.67 30.87 30.73 30.49
1955 30.67 30.77 31.37 31.41 31.57 31.27 31.27 30.89 30.94 31.39 30.78 30.79
1956 30.50 31.10 31.02 31.21 31.27 30.85 30.56 31.15 31.33 31.28 31.14 31.01
1957 31.22 31.30 31.17 31.28 31.44 31.20 31.15 31.35 31.24 31.12 31.35 31.29
1958 31.05 30.82 30.89 31.01 31.01 30.78 30.53 31.04 31.22 31.05 30.96 30.86
1959 30.75 30.66 30.99 31.04 31.20 31.19 30.57 30.83 31.14 30.99 31.07 30.91
1960 30.99 30.85 31.16 31.14 31.13 31.06 30.66 31.02 31.04 31.21 31.15 30.84
1961 30.63 30.65 30.43 30.75 30.99 30.52 30.60 31.08 31.42 31.56 31.52 31.35
1962 31.22 31.29 31.49 31.66 31.44 31.52 31.28 31.31 31.07 31.48 31.13 30.74
1963 30.75 30.98 31.04 31.08 31.19 31.26 31.16 31.18 31.36 31.33 31.00 30.79
1964 30.67 30.70 31.15 31.42 31.68 31.49 30.85 30.75 31.14 31.22 31.31 31.16
1965 30.47 30.86 31.21 31.61 31.51 31.24 31.65 31.55 31.40 31.77 31.25 30.98
1966 30.83 30.87 31.03 31.13 31.35 31.45 31.35 31.14 31.42 31.50 31.62 31.07
1967 30.86 30.75 30.94 30.98 31.36 31.08 30.56 30.92 31.05 31.26 30.83 31.15
1968 30.93 30.64 30.69 30.85 31.28 31.02 30.64 30.96 31.09 31.23 31.01 30.67
1969 30.55 30.75 30.94 31.08 31.06 30.83 30.86 31.20 31.07 31.12 31.42 31.15
1970 31.00 30.74 31.05 31.50 31.71 31.24 31.19 31.65 31.79 32.10 31.84 31.42
1971 31.25 31.04 31.10 30.91 31.06 31.12 30.81 30.59 30.73 31.21 31.57 31.05
1972 30.94 30.89 30.05 30.27 30.69 30.33 29.82 30.40 30.84 31.37 31.80 31.53
1973 31.25 31.09 31.45 31.66 31.94 31.77 31.30 31.62 31.83 31.95 31.64 31.12
1974 31.14 30.92 30.97 31.21 31.55 31.06 30.92 30.53 31.32 31.75 32.11 31.81
1975 31.75 31.61 31.59 32.00 32.14 32.17 31.82 31.69 31.69 32.12 31.42 30.91
1976 30.85 31.07 31.08 31.34 31.56 31.65 31.51 31.34 30.72 30.72 31.13 31.26
1977 31.20 31.40 30.86 31.59 31.46 31.24 31.54 30.97 31.31 31.67 31.52 30.73
1978 30.75 30.67 30.73 30.91 31.29 31.29 31.15 31.53 31.20 31.18 31.25 31.69
1979 31.44 31.24 31.41 31.60 31.56 31.59 31.45 31.63 31.52 31.45 31.45 31.50
1980 31.07 31.48 31.38 31.71 31.71 32.01 31.92 31.78 31.93 31.94 32.06 31.75
1981 31.15 31.41 31.16 31.62 31.88 31.90 32.15 32.25 32.29 32.03 31.61 31.25
1982 31.20 31.08 30.77 31.07 31.55 31.71 31.57 31.29 31.33 31.42 31.21 30.85
1983 30.87 30.57 30.45 30.81 30.93 31.03 31.10 31.01 31.08 31.27 31.06 30.58
1984 30.46 30.54 30.46 30.87 31.35 31.34 31.11 31.46 31.35 31.27 31.02 31.08
1985 31.18 31.21 31.81 31.63 31.93 31.60 31.57 31.87 32.05 31.96 31.45 31.72
1986 31.54 31.16 30.94 31.27 31.64 31.25 31.36 31.17 31.67 31.80 31.82 31.50
1987 30.98 31.02 31.03 31.29 31.43 31.54 31.22 31.67 31.83 31.72 31.87 31.44
1988 31.34 31.40 31.61 31.77 31.70 31.67 31.73 31.83 31.78 31.90 31.59 31.41
1989 31.44 31.42 31.46 31.39 31.89 31.99 31.23 32.47 31.81 32.55 32.12 31.71
1990 31.80 31.54 31.37 31.57 31.76 31.37 31.81 31.21 31.29 31.84 31.43 30.56
1991 30.99 30.95 30.92 30.87 31.60 30.85 30.98 31.26 31.07 31.21 31.46 31.17
1992 30.96 30.51 30.75 31.12 30.90 31.00 30.92 30.56 30.88 31.12 30.91 30.52
1993 30.62 30.35 30.51 30.83 30.71 30.21 30.50 30.76 30.78 30.97 31.10 30.85
1994 30.84 30.64 30.73 31.78 31.53 31.85 31.04 31.34 31.22 31.44 31.57 31.29
1995 30.83 30.76 30.79 30.82 31.02 31.09 30.82 31.23 31.32 31.55 31.25 30.40
1996 30.26 30.20 30.36 30.71 30.84 31.04 30.44 30.88 31.18 31.33 31.27 30.76
1997 30.53 30.41 30.73 30.64 30.43 30.58 30.34 29.90 30.74 30.58 30.49 30.52
1998 30.62 30.39 30.50 30.57 31.08 30.66 30.89 30.92 31.04 31.34 31.20 30.79
1999 30.58 30.32 30.58 30.68 30.73 30.72 30.24 30.29 30.06 30.80 31.26 30.71
2000 30.82 30.80 30.91 31.17 31.07 30.90 30.55 30.70 30.78 30.96 31.25 31.40
2001 31.37 31.19 31.67 31.82 31.79 31.81 31.42 31.37 31.32 31.61 31.49 31.07
2002 30.84 30.81 31.17 31.35 31.41 31.31 30.82 30.76 31.28 31.38 31.75 31.43
2003 31.01 31.05 30.91 30.73 31.17 30.80 31.16 31.21 31.45 31.69 31.05 31.09
2004 30.92 30.71 30.99 31.15 31.25 31.38 31.15 31.38 31.48 31.15 31.17 31.11
2005 30.92 30.58 31.05 31.12 31.11 31.15 30.83 30.83 31.16 31.41 31.17 31.21
2006 30.80 30.23 31.19 31.21 31.08 31.09 30.81 31.00 31.48 31.54 31.15 30.98
2007 30.65 30.80 30.84 30.83 30.82 30.88 30.65 30.48 30.79 31.23 31.09 31.10
2008 30.76 30.86 31.06 31.20 31.50 31.19 31.31 31.30 31.13 31.53 31.23 31.53
2009 31.25 31.52 31.43 30.04 30.50 31.31 31.23 31.39 30.97 31.32 31.27 30.90
2010 30.95 30.84 31.04 30.98 31.32 31.00 30.62 31.01 31.23 31.26 31.47 31.28
2011 30.57 30.92 30.85 30.75 30.76 30.75 30.34 30.46 30.86 30.99 31.47 31.20
2012 31.30 31.31 31.06 30.84 30.69 31.12 30.56 30.39 30.59 31.10 30.92 30.54
2013 30.54 31.10 31.27 31.27 31.42 31.09 30.26 31.09 31.00 30.97 31.29 31.45
2014 31.49 31.43 31.01 30.89 31.06 30.54 30.47 30.42 31.00 31.25 30.53 30.39
2015 29.99 30.34 30.47 30.48 30.90 30.77 31.11 31.78 31.46 31.62 31.62 31.36
2016 31.31 30.91 30.74 30.82 30.94 30.88 30.91 30.88 31.66 31.87 31.45 31.62
2017 31.59 31.34 31.31 31.19 31.17 30.99 30.99 31.33 31.67 32.01 31.83 31.39
2018 31.35 31.14 31.30 30.96 31.22 30.72 29.93 30.37 30.93 31.10 31.12 30.96
2019 30.67 ——- 30.85 ——- ——- 31.25 31.78 31.93 —— – —— – —– —
Year -Jan — Feb -Mar -Apr -May -Jun – Jul -Aug – Sep – Oct – Nov – Dec