Year	Current U.S. Dollars
1991-01-01	479.546196225167
1992-01-01	305.554258433732
1993-01-01	249.412072448661
1994-01-01	282.422062579514
1995-01-01	359.767656488002
1996-01-01	365.011007135980
1997-01-01	411.607371644310
1998-01-01	450.919282254115
1999-01-01	494.233655693391
2000-01-01	462.481438106584
2001-01-01	413.737737605203
2002-01-01	393.016060861473
2003-01-01	329.782094609998
2004-01-01	387.942891069774
2005-01-01	465.310386508996
2006-01-01	505.470620633981
2007-01-01	615.820230827879
2008-01-01	674.756414674589
2009-01-01	668.297604584601
2010-01-01	662.279518162433
2011-01-01	740.935845216079
2012-01-01	766.843762318888
2013-01-01	810.265607301884
2014-01-01	830.113881624145
2015-01-01	814.546395216916
2016-01-01	734.802591238931
2017-01-01	765.683924629642