1961 -10.0 -8.5 -999 -15.9 -17.0 -18.3 -21.3 -21.1 -19.9 -14.9 -11.7 -9.5 1962 -8.9 -10.3 -14.7 -17.0 -21.1 -17.1 -23.0 -22.8 -20.3 -20.5 -14.2 -10.3 1963 -7.8 -10.8 -14.3 -20.2 -18.9 -19.6 -19.9 -17.3 -20.2 -20.6 -14.4 -8.6 1964 -8.7 -11.2 -14.4 -17.4 -18.7 -18.8 -19.3 -21.7 -24.7 -19.4 -12.6 -8.8 1965 -9.0 -10.3 -13.1 -16.5 -15.8 -17.6 -23.6 -21.6 -23.8 -19.2 -13.1 -8.7 1966 -9.4 -10.9 -10.9 -16.2 -16.2 -21.4 -21.3 -24.2 -19.8 -18.4 -13.0 -9.6 1967 -7.1 -12.0 -13.4 -18.2 -17.5 -18.1 -20.5 -21.6 -21.3 -18.3 -13.3 -8.0 1968 -9.0 -11.9 -12.8 -16.0 -16.8 -18.6 -22.8 -23.0 -21.9 -16.9 -11.7 -9.5 1969 -8.0 -10.8 -13.4 -13.0 -16.7 -17.6 -22.9 -24.6 -21.9 -16.6 -12.8 -8.5 1970 -8.9 -11.9 -12.5 -17.2 -18.5 -20.8 -23.4 -23.4 -19.6 -16.6 -12.3 -8.1 1971 -7.4 -8.1 -999 -16.8 -19.9 -22.3 -21.9 -22.3 -21.0 -17.6 -13.5 -8.4 1972 -7.8 -9.7 -14.9 -14.4 -17.5 -19.3 -24.2 -19.0 -20.2 -20.1 -13.0 -10.0 1973 -7.7 -11.3 -13.5 -15.2 -16.3 -17.8 -21.8 -24.2 -20.7 -16.5 -11.2 -9.5 1974 -7.5 -10.7 -12.9 -16.7 -15.6 -19.9 -21.0 -20.7 -20.6 -18.6 -13.5 -8.3 1975 -7.4 -10.5 -12.3 -17.8 -15.4 -21.6 -22.5 -22.3 -20.6 -19.2 -11.7 -10.4 1976 -9.0 -11.7 -14.7 -16.5 -20.2 -16.8 -21.9 -23.5 -20.9 -19.1 -13.6 -7.8 1977 -7.2 -10.9 -13.0 -14.8 -16.2 -18.2 -19.0 -20.1 -22.2 -18.4 -15.0 -9.4 1978 -9.6 -9.9 -15.0 -16.6 -16.6 -20.9 -19.8 -21.3 -21.0 -17.2 -13.5 -8.4 1979 -8.1 -11.2 -14.0 -13.7 -17.4 -20.6 -24.1 -24.0 -20.1 -17.0 -11.9 -8.3 1980 -7.9 -11.5 -13.3 -15.9 -15.3 -19.2 -19.1 -21.3 -19.2 -19.0 -11.6 -9.2 1981 -8.1 -9.4 -14.2 -17.1 -17.5 -20.4 -18.0 -19.9 -22.3 -19.5 -12.0 -7.6 1982 -8.5 -12.2 -14.1 -11.3 -14.9 -20.8 -20.0 -21.2 -21.7 -17.5 -12.3 -7.7 1983 -8.2 -10.6 -14.2 -14.8 -15.4 -18.6 -21.5 -20.5 -19.6 -17.8 -14.8 -10.5 1984 -7.4 -11.1 -13.0 -17.4 -16.1 -21.1 -19.9 -22.3 -19.8 -19.6 -13.9 -7.9 1985 -7.1 -10.2 -12.2 -14.8 -19.6 -18.7 -20.1 -20.4 -21.6 -18.6 -14.8 -9.3 1986 -9.0 -9.4 -13.6 -16.4 -18.4 -20.3 -19.3 -19.1 -20.0 -20.0 -11.4 -8.7 1987 -6.7 -10.5 -12.3 -16.1 -19.5 -18.8 -20.1 -23.2 -24.4 -18.8 -11.9 -8.0 1988 -7.3 -9.9 -10.6 -16.3 -17.6 -17.0 -20.2 -21.6 -20.1 -18.0 -12.7 -7.7 1989 -8.2 -9.3 -13.5 -16.9 -20.9 -19.6 -22.2 -23.5 -21.0 -18.8 -12.9 -9.4 1990 -8.0 -10.1 -13.3 -15.1 -17.7 -20.9 -16.7 -22.3 -23.0 -16.2 -11.8 -7.4 1991 -7.2 -9.6 -13.9 -16.2 -16.7 -18.8 -20.5 -19.5 -21.1 -17.6 -14.2 -7.9 1992 -7.7 -10.2 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999 1993 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999 1994 -999 -12.1 -14.2 -16.5 -18.7 -17.9 -20.0 -20.7 -19.5 -17.2 -13.6 -8.8 1995 -9.0 -10.4 -13.7 -15.9 -19.3 -20.1 -20.0 -21.4 -20.6 -16.2 -14.4 -8.5 1996 -8.7 -8.6 -12.8 -14.3 -999 -999 -999 -999 -999 -999 -999 -999 1997 -999 -999 -999 -999 -999 -999 -22.2 -20.7 -20.9 -19.0 -11.8 -9.1 1998 -8.3 -10.1 -12.5 -18.4 -15.6 -19.9 -19.7 -22.4 -21.7 -19.8 -13.8 -9.6 1999 -8.8 -11.0 -14.3 -18.1 -18.7 -18.4 -20.4 -18.5 -19.8 -17.8 -13.1 -10.4 2000 -9.5 -11.4 -17.3 -17.7 -18.8 -17.9 -21.7 -21.9 -20.3 -19.4 -13.0 -10.0 2001 -9.2 -10.6 -13.9 -16.7 -16.9 -17.6 -20.6 -23.0 -22.3 -18.6 -12.1 -7.7 2002 -7.5 -10.9 -13.6 -13.7 -999 -18.0 -18.4 -18.8 -21.4 -16.2 -15.1 -9.5 2003 -8.5 -8.9 -13.6 -14.6 -17.7 -20.0 -21.3 -19.9 -21.5 -18.5 -12.4 -7.5 2004 -7.2 -9.5 -12.3 -17.3 -19.2 -19.0 -23.4 -22.3 -20.9 -16.3 -12.8 -7.1 2005 -6.9 -9.2 -12.0 -15.6 -19.2 -19.2 -20.4 -20.7 -21.8 -18.2 -16.7 -9.6 2006 -7.6 -11.2 -13.9 -16.1 -17.6 -17.5 -23.4 -19.2 -20.6 -19.6 -12.2 -9.1 2007 -7.1 -10.9 -13.5 -16.4 -16.5 -17.8 -18.3 -20.2 -22.1 -16.6 -9.7 -8.6 2008 -9.4 -10.7 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999