Year	current US$
1977	20372054.64540392
1978	18984660.95920759
1979	2938111.9263496595
1980	378645.249621876
1981	3205370.56651064
1982	2358445.68882843
1983	4416557.344122
1984	20544371.3367111
1985	14058581.5529477
1986	14339923.024784904
1987	18067685.198136494
1988	19150693.674146302
1989	28366033.155018702
1990	23469799.5580332
1991	18407915.0061483
1992	13918073.735391
1993	15704758.756796498
1994	23405781.870509803