Year annual % 1961 57.476635514018696 1962 10.979228486646884 1963 18.823529411764707 1964 0.8550855085508551 1965 -2.0526550647032575 1966 5.831435079726652 1967 15.312096427034009 1968 12.681524620151565 1969 8.441558441558442 1970 42.21556886227545 1971 -15.967776584317939 1972 32.369557992688605 1973 17.464609204503756 1974 28.73466837657427 1975 28.37584132619829 1976 19.38080125749873 1977 28.717145285754764 1978 32.51628274352898 1979 37.429280542500074 1980 20.198156370759314 1981 30.763156260259265 1982 15.71579790193657 1983 7.5243596133735995 1984 26.04980912561353 1985 81.10758580905683 1986 34.05000796305144 1987 127.12367827016753 1988 57.22655228330805 1989 162.8106597464817