Year	constant 2015 US$
1960	2379700000
1961	3329360000
1962	4333200000
1963	4242400000
1964	6030510000
1965	6409270000
1966	6614290000
1967	6034050000
1968	6526690000
1969	5885480000
1970	5678220000
1971	5912220000
1972	6046760000
1973	6359170000
1974	9123960000
1975	10854050000
1976	9971840000
1977	10869920000
1978	12587460000
1979	14435370000
1980	14977550000
1981	15333500000
1982	16163860000
1983	16044080000
1984	17204940000
1985	19396700000
1986	19560350000
1987	18945550000
1988	20152940000
1989	20952590000
1990	22167840000
1991	22595580000
1992	22064640000
1993	20437190000
1994	22485040000
1995	20260810000
1996	17743910000
1997	16902380000
1998	17273440000
1999	16538070000
2000	16600600000
2001	20653400000
2002	25440120000
2003	29354560000
2004	28358770000
2005	28944450000
2006	31771980000
2007	33553290000
2008	34605100000
2009	39943860000
2010	42372790000
2011	40534970000
2012	38723130000
2013	36931930000
2014	34686360000
2015	37133350000
2016	36540020000
2017	38857910000