d 6YEARN MONTHN H2OCONTN  1946 4 24.1 1947 4 9.5 1948 4 21.0 1949 4 23.0 1950 4 25.7 1951 4 22.3 1952 4 34.9 1953 4 26.9 1954 4 23.2 1955 4 14.4 1956 4 32.3 1957 4 21.6 1958 4 29.2 1959 4 9.2 1960 4 14.8 1961 4 24.3 1962 4 24.3 1963 4 2.5 1964 4 23.5 1965 4 10.9 1966 4 14.3 1967 4 22.7 1968 4 12.5 1969 4 26.6 1970 4 16.2 1971 4 26.2 1972 4 27.1 1973 4 15.6 1974 4 18.4 1975 4 36.7 1976 4 23.2 1977 4 9.4 1978 4 11.5 1979 4 11.3 1980 4 16.9 1981 4 11.3 1982 4 18.3 1983 4 29.5 1984 4 23.9 1985 4 22.0 1986 4 15.4 1987 4 18.0 1988 4 7.4 1989 4 23.4 1990 4 17.4 1991 4 9.8 1992 4 3.0 1993 4 20.4 1994 4 10.2 1995 4 19.2 1996 4 23.0 1997 4 7.3 1998 4 20.0 1999 4 29.5