Year	current US$
1970	43483283.81922863
1986	48787370.843642354
1987	35718623.96039629
1988	25643795.713016786
1989	40878333.20500057
1990	49874435.110101864
1991	24157844.38897867
1992	14246247.874352241
1993	20885160.995764256
1994	41623939.234098464
1995	49037386.410425365
1996	49034605.55292413
1997	34821691.84474306
1998	43733768.177582994
1999	42027938.61829715
2000	30099418.87784513
2001	30373576.861158274
2002	41885567.884258896
2003	50933369.0513553
2004	50854684.071552046
2005	61269254.751128145
2006	60361800.08724898
2007	62898597.98193387
2008	88458945.42649493
2009	83198461.10623813
2010	85528007.89785999
2011	106452664.94518606
2012	93323691.7743591
2013	96816014.73992719
2014	106073172.2097845
2015	102088643.04305427
2016	107769819.22454448
2017	119655889.64564693
2018	174277823.91223747