Year	US Dollars
1970	37033000
1971	34634000
1972	32581000
1973	36935000
1974	36186000
1975	33745000
1976	40781000
1977	61097000
1978	148245000
1979	183129000
1980	207636000
1981	185847000
1982	205659000
1983	237054000
1984	191399000
1985	236548000
1986	273384000
1987	302734000
1988	259450000
1989	271308000
1990	256770000
1991	260466000
1992	237879000
1993	228075000
1994	240650000
1995	249458000
1996	234630000
1997	408840000
1998	301144000
1999	341611000
2000	334314000
2001	342241000
2002	391008000
2003	423425000
2004	426174000
2005	475237000
2006	431103000
2007	429288000
2008	432826000
2009	516295000
2010	701721000
2011	643917000
2012	480209000
2013	458031000
2014	416586000
2015	390848000
2016	497239000