Year	US Dollars
1970	1000571000
1971	1079130000
1972	1229411000
1973	1245693000
1974	1600895000
1975	1865319000
1976	2325634000
1977	3344454000
1978	5029136000
1979	6644776000
1980	8297077000
1981	10851628000
1982	12237902000
1983	13902415000
1984	15012833000
1985	17545477000
1986	18537201000
1987	20385277000
1988	21763489000
1989	23536744000
1990	28165123000
1991	37772316000
1992	41864437000
1993	52717187000
1994	65596256000
1995	100092688000
1996	112879505000
1997	109730683000
1998	104943986000
1999	96903111000
2000	79830059000
2001	67296714000
2002	62922123000
2003	58452978000
2004	58416706000
2005	58466721000
2006	62493472000
2007	62779005000
2008	66618743000
2009	80824069000
2010	106357875000
2011	109943316000
2012	134256717000
2013	137353246000
2014	135291566000
2015	129654081000
2016	121497197000