Year	constant 2015 US$
1991	310000
1992	27580000
1993	153700000
1994	244080000
1995	256710000
1996	378900000
1997	314430000
1998	274700000
1999	322680000
2000	235870000
2001	408290000
2002	424750000
2003	277740000
2004	354070000
2005	320080000
2006	380470000
2007	375020000
2008	873750000
2009	878400000
2010	608160000
2011	535740000
2012	610030000
2013	592380000
2014	519840000
2015	453920000
2016	462740000
2017	435880000