Year	current US$
1968	17600000
1970	27200000
1971	30600000
1972	32000000
1973	42700000
1974	43103000
1975	37743000
1976	37960000
1977	34844000
1978	48726000
1979	60942000
1980	55025000
1981	51633000
1982	62768051.52
1983	65586463.96
1984	48994316.419999994
1985	57584375.28
1986	59004960.22
1987	84635204.18
1988	94912717.45
1989	125424089.60000001
1990	124305918.1
1991	117556618.4
1992	115958266.30000001
1993	130655530.5
1994	154268600.3
1995	138441095.10000002
1996	110281818.7
1997	84402948.42999999
1998	93505956.78
1999	89946993.77000001
2000	71403625
2001	61078532
2002	51152268
2003	68824217
2004	62596845
2005	128996086.99999999
2006	113008469
2007	153537576
2008	193148498
2009	187152278
2010	177531472
2011	237782868
2012	241177808
2013	261285153.99999997
2014	272495234
2015	222957293
2016	245773513
2017	277316233
2018	265034711.00000003
2019	273697419
2020	283575621