Year US Dollars 1960 10.19108 1961 53.26569 1962 49.35459 1963 20.20457 1964 25.1604 1966 51.60339 1967 1937.14761 1974 165.58249 1975 235.36278 1976 248.36977 1977 193.79845 1978 109.07057 1979 158.14638 1980 414.97886 1981 332.98465 1982 319.62318 1983 250.91351 1984 144.27978 1985 154.52204 1986 104.71587 1987 148.75681 1988 133.62571 1989 382.34709 1990 356.66262 1991 374.14543 1992 330.17723 1993 196.38089 1994 636.33727 1995 80.90981 1996 66.77704 1997 100.58631 1998 61.32397 1999 130.7056