Year	constant 2015 US$
1975	110646000
1976	103589000
1977	64375000
1978	72795000
1979	71201000
1980	89109000
1981	13666000
1982	6836000
1983	4330000
1984	9529000
1985	43450000
1986	31725000
1987	19237000
1988	16542000
1989	9635000
1990	3469000
1991	1337000
1998	28060000
1999	32636000
2000	47237000
2001	53016000
2002	20733000
2003	37306000
2004	144560000
2005	217574000
2006	300376000
2007	312468000
2008	272950000
2009	336705000
2010	323570000
2011	340386000
2012	368238000
2013	412735000
2014	380317000
2015	440890000
2016	691057000