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	33141760000
1991	34438430000
1992	28159540000
1993	25705070000
1994	25869690000
1995	23199920000
1996	23144190000
1997	21735670000
1998	24091230000
1999	25459010000
2000	23564310000
2001	25237170000
2002	25827320000
2003	25667330000
2004	26218700000
2005	48161870000
2006	32632230000
2007	30436940000
2008	33600090000
2009	27987330000
2010	24829810000
2011	27402830000
2012	26234170000
2013	29292270000
2014	30625630000
2015	30121620000
2016	31439730000
2017	28775210000