Rok Rocni_prumer 1961 1962 1963 6.2 1964 6.5 1965 5.7 1966 7.3 1967 7.3 1968 6.7 1969 6.4 1970 1971 6.8 1972 6.7 1973 6.5 1974 7.4 1975 7.3 1976 1977 6.7 1978 5.9 1979 6.3 1980 5.4 1981 6.6 1982 6.9 1983 7.2 1984 6.1 1985 5.6 1986 6.3 1987 5.9 1988 7.2 1989 7.7 1990 7.6