Year	current US$
1969	2700000
1970	4600000
1971	5700000
1972	6000000
1973	4900000
1974	8800000
1975	9400000
1976	13900000
1977	9000000
1978	9300000
1981	26771818.18
1982	20859090.91
1983	18291818.18
1984	9981818.182
1985	15038949.280000001
1986	15948181.82
1987	19175158.43
1988	27472456.88
1989	25596852
1990	22902589.96
1991	28198687.759999998
1992	27381080.36
1993	21809209.150000002
1994	18080811.78
1995	11196216.31
1996	13978821.76
1997	6010319.829
1998	4032013.5009999997
1999	11527568.58
2000	6865999
2001	7663301
2002	9371889
2003	6437713
2004	7660072
2005	3731864
2006	2588359
2007	1691458
2008	4289724
2009	12585478
2010	14125904
2011	26505100
2012	20595405
2013	16565842
2014	25676661
2015	15469194
2016	29825131
2017	38411821
2018	46214071
2019	48963184
2020	52458293