Year	US Dollars adjusted for inflation)
1974	45621.36146
1975	43925.2391
1976	50722.60813
1977	54151.70302
1978	55752.53855
1979	66001.5809
1980	59391.95115
1981	46156.22482
1982	46575.77808
1983	45483.63118
1984	44479.35391
1985	42589.6833
1986	40274.33884
1987	39933.75513
1988	39243.01702
1989	37732.37517
1990	37071.7353
1991	37162.5406
1992	37838.32056
1993	36904.47506
1994	37043.18167
1995	37703.79173
1996	37833.36477
1997	36400.03739
1998	35382.14265
1999	35672.33991
2000	35923.40183
2001	36162.97793
2002	36832.26623
2003	37202.35794
2004	36752.04732
2005	36325.12073
2006	37401.05316
2007	36997.80726
2008	35860.38878
2009	34812.71469
2010	35268.10117
2011	36092.09698
2012	35899.03737
2013	34618.97291
2014	33313.83278
2015	32661.85702
2016	31430.96266
2017	31439.92372