Year	constant 2015 US$
1973	40000
1974	17360000
1975	6260000
1976	10320000
1977	7400000
1978	6320000
1979	4540000
1980	13470000
1981	8240000
1982	7060000
1983	6610000
1984	8620000
1985	10360000
1986	11240000
1987	13100000
1988	23020000
1989	22040000
1990	11890000
1991	10100000
1992	10280000
1993	14300000
1994	7980000
1995	4340000
1996	8020000
1997	9190000
1998	8580000
1999	6030000
2000	5420000
2001	14160000
2002	36270000
2003	50000
2004	-240000
2005	2650000
2006	5250000
2007	3020000
2008	39170000
2009	2680000
2010	10120000
2011	12870000
2012	19330000
2013	26460000