Year	constant 2015 US$
1976	11340000
1977	10460000
1978	9140000
1979	8080000
1980	5270000
1981	5410000
1982	5530000
1983	4620000
1984	5140000
1985	12210000
1986	12510000
1987	7610000
1988	5690000
1989	8970000
1990	17660000
1991	83750000
1992	145230000
1993	137880000
1994	203690000
1995	199420000
1996	208590000
1997	299450000
1998	244900000
1999	258540000
2000	253880000
2001	276790000
2002	266700000
2003	291230000
2004	274750000
2005	232750000
2006	214090000
2007	223450000
2008	234440000
2009	357510000
2010	286520000
2011	310460000
2012	404590000
2013	403940000
2014	294390000
2015	245540000
2016	325670000
2017	775550000