Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 1946 4.3 8.1 7.2 1947 5.6 9.5 7.5 1948 2.7 8.4 5.1 1949 3.4 4.7 4.4 1950 5.1 7.0 9.2 1951 2.4 4.8 8.3 1952 4.8 6.8 3.6 1953 8.1 8.0 6.3 1954 4.8 8.7 5.9 1955 1.3 7.9 8.4 1956 4.4 7.7 5.3 1957 3.0 8.3 5.6 1958 3.2 5.8 8.7 1959 3.6 7.7 7.9 1960 4.8 9.3 7.0 1961 5.8 8.6 6.0 1962 2.0 5.6 4.5 1963 3.3 5.4 7.0 1964 1.9 6.0 4.9 1965 -11.8 -10.2 -11.7 -5.7 -3.9 3.3 5.1 5.6 1.9 -2.4 -10.6 -14.2 1966 -13.7 -18.7 -13.2 -10.1 -3.1 5.6 7.1 4.5 -1.8 -7.0 -6.8 -13.1 1967 -13.4 -9.5 -7.3 -5.1 -0.5 2.5 5.9 6.8 3.7 -4.7 -4.7 -14.1 1968 -15.2 -12.5 -10.3 -5.5 -4.5 3.6 5.2 4.6 0.4 -9.3 -5.7 -6.7 1969 -11.8 -14.1 -9.5 -7.3 -3.6 4.7 7.0 9.5 0.8 -2.6 -10.0 -10.3 1970 -11.6 -15.4 -11.3 -9.5 -1.2 7.4 7.7 6.9 1.2 -3.0 -10.5 -8.3 1971 -11.5 -13.6 -13.2 -8.6 -2.8 4.0 5.8 6.0 1.3 -3.7 -9.7 -8.1 1972 -8.1 -8.1 -8.5 -7.2 -1.4 6.7 9.5 6.7 0.8 -3.2 -8.6 -4.4 1973 -8.4 -11.6 -7.9 -8.5 -2.3 3.4 9.5 4.1 -0.6 -6.7 -9.7 -12.5 1974 -9.0 -9.8 -7.3 -3.9 -0.9 4.7 7.0 6.2 3.0 -5.6 -9.5 -9.1 1975 -10.7 -7.6 -7.6 -7.6 -1.2 0.9 4.6 4.5 1.2 -3.0 -5.6 -11.0 1976 -14.1 -7.8 -10.1 -7.6 0.5 2.7 6.4 6.7 -1.3 -5.9 -7.9 -11.2 1977 -14.2 -12.9 -8.9 -10.1 -3.0 1.7 6.1 6.0 -0.2 -3.6 -7.3 -9.5 1978 -12.9 -13.6 -11.5 -8.6 -1.5 4.4 7.8 4.9 -0.4 -5.4 -6.9 -13.5 1979 -13.1 -11.7 -11.0 -7.0 -2.2 4.8 8.4 6.3 0.6 -4.9 -9.5 -9.6 1980 -12.2 -9.7 -11.3 -4.9 -0.8 7.3 9.6 6.6 2.4 -5.4 -9.3 -11.5 1981 -12.0 -10.2 -13.7 -6.3 1.0 1.1 7.3 5.3 1.6 -4.4 -9.0 -14.8 1982 -12.6 -7.3 -9.3 -6.5 -2.0 0.0 6.3 6.0 0.0 -3.2 -6.4 -8.8 1983 -10.4 -8.1 -11.3 -5.4 0.4 2.3 6.7 3.5 2.5 -4.5 -10.1 -10.6 1984 -12.9 -8.3 -11.0 -4.7 1.5 4.3 6.4 4.8 0.7 -4.3 -7.0 -6.6 1985 -12.4 -15.8 -9.6 -9.4 -2.6 4.0 7.9 6.1 0.9 -2.2 -9.0 -15.0 1986 -14.9 -10.2 -7.1 -7.5 1.0 6.2 7.6 3.8 -1.1 -2.7 -6.3 -15.8 1987 -13.7 -14.2 -12.4 -8.0 -2.6 2.8 6.0 3.7 0.8 0.3 -7.7 -10.7 1988 -11.4 -13.3 -12.4 -8.4 -0.9 4.8 9.2 5.8 0.2 -6.3 -10.3 -11.1 1989 -9.7 -9.9 -8.5 -4.3 -1.1 2.8 5.3 6.0 2.0 -4.3 -5.7 -11.5 1990 -11.5 -7.4 -9.0 -5.2 -1.7 3.9 7.3 6.7 0.9 -2.1 -8.4 -6.4 1991 -9.0 -10.0 -9.9 -5.7 -2.7 3.2 7.4 7.6 -0.8 -2.0 -6.5 -6.5 1992 -7.0 -7.5 -7.2 -8.7 0.7 5.7 5.5 4.2 2.6 -8.5 -10.0 -6.1 1993 -8.7 -8.3 -8.1 -6.8 -0.2 1.8 7.0 5.2 -0.2 -6.1 -4.7 -11.8 1994 -13.1 -9.9 -9.4 -4.3 -2.6 2.2 7.7 6.7 0.7 -4.2 -7.1 -6.4 1995 -9.5 -10.0 -8.9 -7.9 -2.7 3.9 5.6 5.3 1.6 -3.4 -8.2 -9.8 1996 -4.9 -12.9 -8.2 -6.1 -3.3 3.2 7.3 9.2 1.4 -2.4 -8.7 -10.8 1997 -9.6 -11.8 -10.1 -9.4 -2.0 4.7 9.3 8.2 3.0 -4.7 -6.7 -7.1 1998 -9.7 -12.3 -10.4 -11.9 -2.6 2.4 7.9 5.4 2.3 -3.9 -9.7 -8.2 1999 -10.9 -11.8 -9.3 -4.6 -2.5 5.4 6.9 4.2 4.6 -1.3 -3.7 -10.8 2000 -9.0 -9.8 -9.3 -6.2 0.5 3.3 8.1 6.5 3.8 -0.2 -5.8 -8.7 2001 -8.5 -13.6 -12.7 -6.4 -1.1 5.6 7.0 6.9 6.2 -1.8 -7.1 -9.7 2002 -9.2 -10.0 -9.3 -2.9 1.5 7.1 8.7 10.4 1.9 -6.5 -9.3 -10.4 2003 -13.8 -4.8 -7.2 -4.5 0.0 4.8 11.7 7.3 2.1 -4.2 -3.9 -9.2 2004 -10.5 -9.8 -7.7 -3.2 -0.3 2.6 8.4 7.2 2.2 -2.8 -6.6 -6.8 2005 -10.4 -10.2 -8.9 -4.7 -1.9 4.3 9.3 7.3 2.2 0.1 -4.9 -9.4 2006 -7.4 -9.8 -11.6 -5.4 0.7 5.0 8.7 11.0 3.6 -4.4 -5.9 -6.0 2007 -10.3 -13.9 -5.6 -4.3 -0.9 4.6 8.4 7.0 0.8 0.5 -6.9 -4.5 2008 -10.4 -8.9 -12.0 -7.3 -2.1 3.7 8.1 4.8 1.8 -2.9 -7.9 -7.6 2009 -12.8 -12.3 -6.2 0.9 3.3 7.1 7.6 2.5 -4.1 -6.4 -12.2 2010 -10.2 -15.2 -11.8 -6.3 -0.3 2.1 7.3 3.9 3.4 -2.8 -10.5 -11.8 2011 -11.1 -12.9 -9.0 -2.9 -1.3 5.6 8.6 6.2 3.3 -0.5 -1.8 -8.6 2012 -12.5 -11.3 -7.7 -8.9 -3.0 1.4 5.4 5.9 0.9 -5.2 -6.4 -13.3