Year	current US$
1981	2921747037.23443
1982	3007343289.40478
1983	2016774544.45415
1984	1536804660.82607
1985	1430550320.09657
1986	1057333970.55308
1987	860046371.142144
1988	770890961.66369
1989	578738090.334603
1990	659312716.860024
1991	599727145.592275
1992	978662571.347182
1993	596242922.737307
1994	598513641.92808
1995	513854734.223991
1996	465420493.75
1997	496966164.653685
1998	751170664.772727
1999	821347859.659231
2000	1474704210.43627
2001	1473664332.79122
2002	1278635446.54009
2003	998495868.36338
2004	6529666089.48889
2005	8004496320.30032
2006	12102316344.0514
2007	26042051942.6015
2008	31778934789.8706
2009	25247485731.862
2010	32150446845.6001
2011	35174504879.7101
2012	37798278342.6477
2013	36846963216.8593
2014	36750534917.7497
2015	33078318522.6795
2016	21787470810.1242
2017	17376283867.2671