Year	US Dollars adjusted for inflation)
1975	7611.12372
1976	7365.44687
1977	8115.92198
1978	8723.82408
1979	8182.94498
1980	7743.32725
1981	7751.35478
1982	7580.24269
1983	7324.10862
1984	6992.97364
1985	6792.65706
1986	6458.00011
1987	5445.26106
1988	5805.85599
1989	6314.86995
1990	6160.94598
1991	6214.24855
1992	6091.02042
1993	5553.55992
1994	5642.08047
1995	5617.98576
1996	5609.78063
1997	5854.59694
1998	5873.95377
1999	5754.92266
2000	5685.38735
2001	5877.68043
2002	6063.10319
2003	6357.90355
2004	6871.83933
2005	7109.3693
2006	7304.04167
2007	7596.07997
2008	7827.23158
2009	7978.38828
2010	8303.31332
2011	8698.3021
2012	8841.04401
2013	9008.75625
2014	8942.96078
2015	8627.52723
2016	8108.23664
2017	8043.46212