Year	constant 2015 US$
1961	17860000
1967	2950000
1974	40000
1975	840000
1976	1510000
1978	30000
1979	1010000
1980	860000
1981	580000
1982	530000
1983	1020000
1986	580000
1988	30000
1990	140000
1991	1220000
1992	190000
1993	600000
1994	300000
1995	20000
1996	110000
1997	630000
1998	2340000
1999	252360000
2000	378020000
2001	321740000
2002	333260000
2003	223500000
2004	187740000
2005	202570000
2006	224470000
2007	272210000
2008	259230000
2009	210690000
2010	261420000
2011	231150000
2012	238300000
2013	220040000
2014	220100000
2015	214910000
2016	223550000
2017	224480000