1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 | 0. 19 0.26 0. 15 0.24 0.84 3.13 3.03 1.65 0.41 2.05 | 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 | 2.44 2. 74 3. 94 3. 75 2. 23 1.89 1.50 2.59 3. 17 3. 74 | 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 | 4. 93 4.92 5.39 4.91 3. 89 3.90 4. 78 6. 56 7. 38 7.73 | 1990 1991 1992 1993 1994 1995 | 8. 62 9.46 9.74 8.48 8.80 9.56 |