Year	constant 2015 US$
1960	16649240000
1961	20593230000
1962	20326890000
1963	21911740000
1964	21435450000
1965	21968040000
1966	23220020000
1967	23921870000
1968	22431570000
1969	20028250000
1970	20543610000
1971	20806970000
1972	18439050000
1973	20739020000
1974	24705000000
1975	28757700000
1976	27258040000
1977	24201540000
1978	24642370000
1979	23263990000
1980	26927210000
1981	28306070000
1982	25934130000
1983	24740600000
1984	25104780000
1985	26420830000
1986	23838800000
1987	22622950000
1988	22218370000
1989	23218890000
1990	36421310000
1991	41060640000
1992	34597800000
1993	31969960000
1994	32099230000
1995	31489480000
1996	27834180000
1997	25507220000
1998	28817530000
1999	31956250000
2000	30455850000
2001	31102400000
2002	31018950000
2003	30811480000
2004	32106930000
2005	48161870000
2006	32632230000
2007	30436940000
2008	33600090000
2009	27987330000
2010	24829810000
2011	27403060000
2012	26234170000
2013	29292270000
2014	30625630000
2015	30121620000
2016	31439730000
2017	28775210000