Year	US Dollars adjusted for inflation)
1981	2204.63651
1982	2303.54416
1983	2346.87986
1984	2385.94767
1985	2539.42544
1986	2587.93861
1987	2658.45623
1988	2600.62978
1989	2603.5642
1990	2544.34119
1991	2702.44695
1992	2704.63236
1993	2801.39119
1994	2934.33237
1995	3035.55394
1996	3026.63381
1997	3011.52628
1998	3080.347
1999	3184.96516
2000	3275.81211
2001	3375.59386
2002	3470.83324
2003	3522.53194
2004	3488.58299
2005	3521.5071
2006	3470.64655
2007	3304.3607
2008	3385.34811
2009	3442.87215
2010	3548.0684
2011	3631.54327
2012	3650.81925
2013	3524.23207
2014	3581.83661
2015	3694.46241
2016	3792.29015
2017	3862.30442