Year	US Dollars
1962	1560
1963	1700
1964	1880
1965	2040
1966	2210
1967	2370
1968	2560
1969	2820
1970	3010
1971	3240
1972	3670
1973	4690
1974	5780
1975	6700
1976	7120
1977	7790
1978	8810
1979	10810
1980	13080
1981	13200
1982	12060
1983	10470
1984	9850
1985	9800
1986	11350
1987	14490
1988	18540
1989	19520
1990	20660
1991	21550
1992	24010
1993	23770
1994	24550
1995	25910
1996	27270
1997	27090
1998	25960
1999	25560
2000	25140
2001	23930
2002	23170
2003	26020
2004	31500
2005	35990
2006	37930
2007	40230
2008	43490
2009	43740
2010	43790
2011	44190
2012	42970
2013	43360
2014	42960
2015	40730
2016	38780
2017	37970