Year	constant 2015 US$
1991	3920000
1992	33660000
1993	160730000
1994	267380000
1995	270160000
1996	369920000
1997	215520000
1998	256840000
1999	276390000
2000	293540000
2001	295700000
2002	397270000
2003	303520000
2004	288030000
2005	188050000
2006	228710000
2007	354990000
2008	294210000
2009	494200000
2010	323760000
2011	362160000
2012	248070000
2013	251430000
2014	235960000
2015	345210000
2016	326430000
2017	245350000