Year	US Dollars adjusted for inflation)
1970	20202.51373
1971	20656.40023
1972	21333.22046
1973	22551.50626
1974	23409.8294
1975	22561.23431
1976	22570.20086
1977	21614.35777
1978	21676.15931
1979	22238.18203
1980	22495.56419
1981	23452.25014
1982	23436.38751
1983	23927.31628
1984	24858.1523
1985	25103.94523
1986	25789.56174
1987	24465.96857
1988	24887.86738
1989	24898.94207
1990	24830.3943
1991	23267.48489
1992	23317.98565
1993	24559.66983
1994	25499.58554
1995	26279.10376
1996	26735.05261
1997	27180.29549
1998	27227.40963
1999	28491.4184
2000	28972.97624
2001	29896.57091
2002	30868.58816
2003	31639.47936
2004	32191.95726
2005	32887.05461
2006	33324.50326
2007	34256.7377
2008	33442.25803
2009	33743.99323
2010	33692.01083
2011	34337.46265
2012	35003.27667
2013	35436.32332
2014	36142.52008
2015	37038.85488
2016	37528.45833
2017	37852.87359