Year	2011 U.S. Dollars
1983-01-01	25.80
1984-01-01	27.36
1985-01-01	27.93
1986-01-01	27.76
1987-01-01	28.87
1988-01-01	29.62
1989-01-01	31.21
1990-01-01	32.37
1991-01-01	33.58
1992-01-01	35.50
1993-01-01	36.25
1994-01-01	37.23
1995-01-01	39.25
1996-01-01	40.62
1997-01-01	43.84
1998-01-01	45.51
1999-01-01	47.77
2000-01-01	50.15
2001-01-01	51.14
2002-01-01	53.78
2003-01-01	55.88
2004-01-01	56.59
2005-01-01	57.30
2006-01-01	58.14
2007-01-01	59.39
2008-01-01	59.45
2009-01-01	62.53
2010-01-01	64.83
2011-01-01	66.74