Year	constant 2015 US$
1972	90000
1983	30000
1985	13830000
1986	29650000
1987	27230000
1988	33670000
1989	93750000
1990	170370000
1991	249800000
1992	182090000
1993	206670000
1994	180380000
1995	213740000
1996	222560000
1997	217940000
1998	240600000
1999	237580000
2000	224370000
2001	164470000
2002	190610000
2003	179430000
2004	194280000
2005	123820000
2006	160490000
2007	216410000
2008	195330000
2009	313230000
2010	258320000
2011	260580000
2012	250620000
2013	254260000
2014	219140000
2015	143120000
2016	170190000
2017	182150000