1970 38.8
1971 40.5
1972 41.8
1973 44.4
1974 49.3
1975 53.8
1976 56.9
1977 60.6
1978 65.2
1979 72.6
1980 82.4
1981 90.9
1982 96.5
1983 99.6
1984 103.9
1985 107.6
1986 109.6
1987 113.6
1988 118.3
1989 124.0