Year	current US$
1977	27000000
1978	34000000
1979	40296296.2962963
1980	39592592.5925926
1981	39296296.2962963
1982	38296296.2962963
1983	39000000
1984	41777777.7777778
1985	55185185.1851852
1986	75888888.8888889
1987	79777777.7777778
1988	86185185.1851852
1989	85333333.3333333
1990	93092592.5925926
1991	97548148.1481481
1992	99566666.6666667
1993	110425925.925926
1994	126766666.666667
1995	123800000
1996	131600000
1997	138940740.740741
1998	165718518.518519
1999	218037037.037037
2000	235727407.407407
2001	197133111.111111
2002	172622222.222222
2003	179535555.555556
2004	197736925.925926
2005	148871259.259259
2006	162306481.481481
2007	209545888.888889
2008	207800814.814815
2009	187237296.296296
2010	183762222.222222
2011	196181925.925926
2012	206490962.962963
2013	214246185.185185
2014	548311296.296296
2015	578320444.444444
2016	592563555.555555