1983 -999 -999 -999 -999 -999 -999 -59.8 -61.0 -56.8 -57.2 -53.4 -51.1 1984 -48.1 -50.7 -47.8 -52.8 -52.3 -56.9 -57.8 -56.5 -58.3 -55.1 -52.2 -49.6 1985 -48.6 -50.8 -50.5 -49.6 -53.5 -999 -999 -999 -999 -999 -999 -999 1986 -999 -999 -999 -51.8 -55.8 -57.8 -58.1 -57.1 -57.8 -55.0 -50.1 -47.6 1987 -47.7 -49.4 -51.8 -54.6 -55.7 -54.4 -57.6 -58.7 -57.6 -54.5 -52.6 -50.7 1988 -48.3 -49.2 -52.5 -51.8 -56.1 -57.9 -57.6 -59.0 -57.4 -54.8 -50.1 -49.6 1989 -46.0 -49.8 -51.2 -51.1 -54.0 -57.5 -56.9 -57.1 -55.8 -54.6 -54.5 -47.1 1990 -48.3 -48.6 -50.6 -52.1 -56.6 -55.7 -57.4 -58.5 -58.6 -58.8 -52.9 -51.1 1991 -49.1 -49.1 -51.1 -999 -999 -999 -999 -999 -999 -999 -999 -999