Year	US Dollars adjusted for inflation)
1980	4357.69083
1981	4308.16572
1982	4201.2358
1983	4030.33366
1984	3912.04241
1985	3802.98221
1986	3833.09994
1987	3802.39644
1988	3666.32576
1989	3577.41763
1990	3509.35624
1991	3663.71454
1992	3802.63236
1993	3631.58074
1994	3586.94271
1995	3617.29004
1996	3620.88906
1997	3661.05152
1998	3673.8446
1999	3700.59111
2000	3746.71312
2001	3723.5253
2002	3845.05715
2003	3958.87386
2004	4394.41065
2005	4454.63476
2006	4715.10597
2007	4968.66403
2008	5036.2547
2009	4978.68
2010	5191.58308
2011	5351.36975
2012	5502.25887
2013	5679.27865
2014	5901.24288
2015	6120.7454
2016	6028.996
2017	5854.86162