Year	US Dollars
1970	0
1971	0
1972	146504000
1973	497821000
1974	1257485000
1975	1680487000
1976	1993988000
1977	2331731000
1978	2820090000
1979	2967070000
1980	3802227000
1981	4209316000
1982	4940332000
1983	5346290000
1984	5541813000
1985	6530064000
1986	7913830000
1987	9737966000
1988	10275896000
1989	10701054000
1990	12291773000
1991	12997668000
1992	13427958000
1993	14125217000
1994	15490544000
1995	15734746000
1996	15169074000
1997	14257777000
1998	15509849000
1999	16452032000
2000	15602838000
2001	14981002000
2002	16689962000
2003	18442975000
2004	19716789000
2005	18505584000
2006	20162643000
2007	21574985000
2008	23407581000
2009	25437537000
2010	26880728000
2011	27276717000
2012	28558969000
2013	33994737000
2014	35662409000
2015	38688480000
2016	41125641000