Year	2011 U.S. Dollars
1976-01-01	12.77
1977-01-01	13.12
1978-01-01	13.35
1979-01-01	13.73
1980-01-01	14.29
1981-01-01	15.42
1982-01-01	16.19
1983-01-01	17.10
1984-01-01	18.50
1985-01-01	19.31
1986-01-01	19.67
1987-01-01	20.70
1988-01-01	21.82
1989-01-01	22.49
1990-01-01	22.50
1991-01-01	24.11
1992-01-01	24.96
1993-01-01	27.49
1994-01-01	29.21
1995-01-01	30.24
1996-01-01	30.64
1997-01-01	31.32
1998-01-01	30.29
1999-01-01	31.97
2000-01-01	33.50
2001-01-01	32.84
2002-01-01	34.55
2003-01-01	36.44
2004-01-01	38.99
2005-01-01	39.98
2006-01-01	41.14
2007-01-01	41.17
2008-01-01	38.51
2009-01-01	36.70
2010-01-01	40.88
2011-01-01	41.27