Year	US Dollars adjusted for inflation)
1988	473.70255
1989	476.6046
1990	494.2025
1991	488.07672
1992	474.6446
1993	464.53305
1994	456.89312
1995	459.17497
1996	466.81301
1997	470.72237
1998	475.92871
1999	486.41093
2000	497.20418
2001	512.96827
2002	534.69665
2003	555.49604
2004	581.77241
2005	610.82233
2006	620.05971
2007	651.90366
2008	666.81324
2009	680.80613
2010	701.60455
2011	733.6708
2012	747.66445
2013	777.40363
2014	806.15008
2015	835.97095
2016	867.05865
2017	900.52302