Year US Dollars adjusted for inflation) 1961 3000000 1963 1000000 1964 0 1965 7000000 1967 12000000 1968 1000000 1969 1000000 1971 0 1972 0 1974 18000000 1975 6000000 1979 64000000 1980 43000000 1981 0 1983 8000000 1985 6000000 1996 21000000 2018 1000000 2020 1000000