Year	US Dollars adjusted for inflation)
1981	1440.62457
1982	1521.95119
1983	1570.55459
1984	1621.17342
1985	1668.49739
1986	1774.66025
1987	1784.53974
1988	1825.09584
1989	1855.79957
1990	1761.21739
1991	1583.61799
1992	1420.64361
1993	1363.65347
1994	1382.19593
1995	1459.10628
1996	1479.78785
1997	1524.8601
1998	1562.48056
1999	1596.51171
2000	1600.47948
2001	1632.52467
2002	1693.08114
2003	1792.87317
2004	1961.49189
2005	2079.11237
2006	2229.15454
2007	2425.68184
2008	2604.92892
2009	2533.17574
2010	2650.35365
2011	3053.61227
2012	3365.57198
2013	3685.74785
2014	3901.8666
2015	3923.62847
2016	3906.11587
2017	4071.09329