1963 -999 -999 13.1 14.3 14.1 15.1 10.9 13.6 8.5 8.6 7.3 8.2 1964 6.6 7.0 11.2 14.4 12.9 14.3 10.2 12.2 8.7 10.8 7.3 5.3 1965 6.0 8.2 11.9 12.4 12.3 12.2 9.7 9.6 9.7 9.5 8.1 5.2 1966 4.9 8.1 11.3 16.7 15.2 11.2 12.4 8.1 11.6 9.9 8.8 7.2 1967 4.5 6.5 11.0 13.6 11.9 13.0 10.6 10.4 9.7 8.0 8.0 6.6 1968 6.1 9.1 13.2 12.8 14.9 12.9 10.5 11.0 9.5 10.1 8.0 5.5 1969 6.6 8.0 12.7 9.3 13.5 14.3 9.6 9.6 7.4 9.8 8.3 5.5 1970 5.7 8.1 10.8 14.6 11.9 13.4 11.7 9.1 10.1 12.4 9.9 6.8 1971 5.1 9.9 12.1 11.3 13.8 12.6 13.2 11.9 10.9 9.8 8.1 4.9 1972 4.6 7.8 11.7 13.1 12.6 14.7 9.0 10.3 10.8 9.5 8.2 5.8 1973 4.4 8.4 14.0 15.2 16.4 15.6 11.8 11.9 7.6 10.2 6.9 6.6 1974 3.2 7.9 11.9 12.7 15.8 13.5 11.5 -999 10.8 -999 6.7 5.9 1975 5.1 9.3 13.4 14.9 15.2 11.1 10.8 11.1 8.7 8.5 8.5 4.6 1976 5.0 8.0 13.0 16.2 13.9 15.1 12.8 9.1 10.5 7.1 8.3 5.6 1977 4.8 8.4 14.2 15.6 15.9 10.7 14.1 6.8 8.1 9.1 8.1 6.2 1978 6.0 9.2 12.3 15.7 15.3 13.5 13.6 11.1 11.6 7.9 6.8 4.8 1979 6.0 9.8 13.0 13.0 15.4 13.0 9.3 10.8 10.6 8.2 8.8 4.8 1980 8.9 9.9 12.1 14.9 17.0 14.1 13.6 10.8 10.4 10.4 7.7 5.9 1981 5.1 8.8 10.0 13.6 15.9 14.2 13.5 11.4 8.2 8.7 7.4 7.7 1982 4.1 8.9 12.6 16.8 17.3 12.8 14.6 10.2 -999 10.3 8.3 6.2 1983 6.0 10.4 13.8 16.8 16.0 12.3 10.0 12.0 10.1 7.8 6.8 4.9 1984 5.8 8.6 13.6 15.5 13.4 11.8 12.6 8.7 9.7 8.1 7.6 5.4 1985 7.2 8.8 12.7 15.0 16.3 10.5 12.9 11.9 11.8 9.6 7.7 8.6 1986 6.6 8.9 12.4 17.6 15.7 13.5 13.2 13.1 12.0 8.1 9.7 7.7 1987 6.5 8.9 14.0 14.4 17.2 14.4 13.6 11.8 13.3 9.5 11.9 5.6 1988 6.2 9.3 13.4 16.2 15.7 15.2 12.1 11.6 10.6 4.8 6.1 4.5 1989 6.3 8.7 14.0 14.5 11.7 14.0 10.7 10.6 6.4 8.2 9.9 6.8 1990 6.4 8.8 12.3 14.2 11.9 16.4 12.1 11.6 9.9 9.2 8.1 7.0 1991 6.8 10.4 9.7 12.4 16.0 12.9 12.9 12.8 11.3 7.3 7.8 5.5 1992 6.1 8.8 14.0 13.5 14.1 12.7 12.9 11.1 11.5 9.6 7.6 6.6 1993 5.7 7.7 14.4 15.0 14.8 14.4 9.5 9.5 10.8 9.8 8.2 7.6 1994 6.1 9.2 14.5 14.8 15.2 12.7 11.7 10.3 10.8 9.4 8.2 7.0 1995 5.5 9.1 13.1 13.3 13.3 14.6 13.2 10.5 9.3 12.0 6.6 6.8 1996 5.6 9.3 11.8 15.1 13.7 11.6 16.0 12.3 11.0 8.6 7.2 5.5 1997 4.8 8.8 10.9 15.1 13.7 14.5 13.2 11.6 11.0 8.7 7.8 6.5 1998 6.0 8.0 13.8 13.9 15.2 11.4 10.2 9.7 9.5 6.8 7.7 5.0 1999 7.6 9.1 11.2 12.7 11.6 11.3 -999 -999 -999 -999 -999 -999