Year	constant 2015 US$
1960	17540000
1961	18460000
1962	20440000
1963	25830000
1964	24680000
1965	33390000
1966	39800000
1967	44070000
1968	54150000
1969	58170000
1970	58350000
1971	45400000
1972	73420000
1973	63420000
1974	58920000
1975	91480000
1976	85710000
1977	65490000
1978	84650000
1979	67460000
1980	95990000
1981	67280000
1982	65360000
1983	66780000
1984	48730000
1985	52960000
1986	67980000
1987	103120000
1988	90830000
1989	76580000
1990	67280000
1991	51160000
1992	63540000
1993	71610000
1994	61550000
1995	55700000
1996	49800000
1997	51860000
1998	61040000
1999	56360000
2000	112660000
2001	108500000
2002	51620000
2003	107850000
2004	165090000
2005	241700000
2006	245250000
2007	261400000
2008	228160000
2009	222290000
2010	300410000
2011	260080000
2012	235830000
2013	236560000
2014	170390000
2015	192390000
2016	175500000
2017	177640000