Year	US Dollars adjusted for inflation)
1975	7618.11875
1976	9236.57836
1977	10746.57195
1978	11539.49139
1979	12584.31728
1980	13164.53487
1981	13273.64598
1982	13907.39773
1983	14563.13774
1984	15634.65778
1985	16199.88765
1986	16608.35265
1987	17589.45345
1988	18908.80065
1989	20122.65312
1990	21156.95134
1991	20768.77571
1992	22124.5271
1993	21747.82876
1994	22559.50146
1995	24030.2363
1996	23965.52557
1997	24234.41822
1998	25192.43326
1999	26114.99869
2000	27317.80369
2001	27998.01692
2002	28619.82646
2003	28974.13482
2004	29895.75294
2005	30565.7818
2006	31415.82316
2007	32236.59055
2008	32651.90559
2009	31223.62178
2010	30818.46396
2011	30138.59351
2012	28775.07467
2013	27130.56836
2014	27045.76793
2015	27738.50325
2016	28448.82236
2017	29432.66573