1971 -999 -999 -8.3 -12.0 -13.2 -12.3 -17.0 -15.6 -17.9 -13.2 -9.9 -3.2 1972 -1.0 -3.7 -8.6 -10.9 -15.6 -14.0 -14.6 -17.2 -16.5 -16.2 -9.2 -3.3 1973 -1.5 -6.0 -8.8 -12.1 -14.0 -15.4 -15.1 -17.8 -17.4 -15.4 -6.6 -2.7 1974 -0.8 -5.2 -8.4 -14.4 -15.5 -12.5 -20.1 -16.6 -16.5 -14.6 -7.1 -1.6 1975 -1.0 -4.9 -8.1 -13.8 -15.8 -18.2 -14.5 -21.5 -19.3 -16.6 -8.4 -3.0 1976 -1.2 -3.8 -9.4 -18.3 -16.8 -19.3 -19.2 -17.2 -19.1 -19.5 -6.3 -0.2 1977 0.5 -4.6 -8.5 -12.6 -16.7 -17.0 -17.5 -15.9 -19.1 -13.6 -7.9 -2.3 1978 -2.6 -3.5 -7.2 -11.8 -16.3 -19.0 -13.4 -21.3 -19.2 -15.1 -7.8 -3.3 1979 -2.7 -4.7 -7.2 -10.9 -16.6 -17.0 -21.1 -15.8 -16.1 -14.4 -7.1 -0.7 1980 -0.8 -3.7 -5.9 -10.6 -13.1 -17.2 -16.1 -17.4 -14.3 -15.9 -6.8 -1.9 1981 -2.4 -3.7 -7.5 -11.2 -14.3 -11.5 -15.1 -14.1 -15.6 -13.5 -8.8 -2.7 1982 -1.2 -3.5 -9.7 -15.3 -13.6 -12.8 -18.1 -20.0 -18.0 -14.1 -7.0 -0.7 1983 -1.5 -3.0 -7.7 -11.8 -12.5 -16.1 -21.2 -20.3 -13.9 -14.1 -8.5 -2.3 1984 -1.4 -4.5 -8.0 -14.7 -13.2 -20.8 -21.6 -16.8 -16.0 -12.2 -8.7 -2.2 1985 -0.2 -4.6 -8.4 -13.1 -16.9 -16.9 -19.6 -18.3 -19.6 -15.3 -7.9 -2.9 1986 -1.6 -2.9 -6.5 -11.5 -14.3 -14.3 -17.0 -16.4 -18.7 -13.4 -8.0 -3.0 1987 -0.8 -4.3 -6.6 -12.5 -16.7 -12.9 -15.6 -18.1 -17.1 -11.5 -8.0 -3.2 1988 -1.7 -4.2 -9.0 -11.3 -17.1 -17.3 -18.8 -18.2 -13.4 -12.6 -7.7 -2.2 1989 -2.0 -5.3 -8.6 -12.7 -18.0 -22.2 -16.2 -19.5 -14.4 -13.5 -8.0 -2.1 1990 -1.4 -4.7 -8.6 -15.6 -14.2 -18.0 -12.6 -19.2 -19.6 -13.6 -7.3 -1.7 1991 -1.5 -4.2 -999 -999 -999 -999 -999 -999 -999 -999 -999 -999