Year	US Dollars adjusted for inflation)
1974	10851.8423
1975	10580.97006
1976	10983.58674
1977	11317.70634
1978	11813.01514
1979	12688.1391
1980	13192.99958
1981	12897.02318
1982	12228.2991
1983	12256.75155
1984	12664.40769
1985	12767.14471
1986	13375.83003
1987	13676.9881
1988	14105.52698
1989	14560.88969
1990	14030.84532
1991	13437.14437
1992	12453.21836
1993	12559.30509
1994	12990.83456
1995	13203.44163
1996	13680.82333
1997	14270.00273
1998	14742.49
1999	14747.96111
2000	15035.4474
2001	14629.16632
2002	14703.12531
2003	14983.54393
2004	15146.96991
2005	15700.07264
2006	16532.82987
2007	16762.70906
2008	16708.74022
2009	15974.09087
2010	15959.02979
2011	16011.6377
2012	16003.55202
2013	15951.20932
2014	15901.90093
2015	15998.0488
2016	16273.40659
2017	16503.47836