Year	2011 U.S. Dollars
1960-01-01	17747
1961-01-01	17862
1962-01-01	18655
1963-01-01	19192
1964-01-01	20023
1965-01-01	21044
1966-01-01	22158
1967-01-01	22472
1968-01-01	23326
1969-01-01	23816
1970-01-01	23585
1971-01-01	24071
1972-01-01	25080
1973-01-01	26281
1974-01-01	25898
1975-01-01	25590
1976-01-01	26707
1977-01-01	27656
1978-01-01	28891
1979-01-01	29467
1980-01-01	29041
1981-01-01	29488
1982-01-01	28638
1983-01-01	29662
1984-01-01	31519
1985-01-01	32531
1986-01-01	33353
1987-01-01	34114
1988-01-01	35196
1989-01-01	36111
1990-01-01	36378
1991-01-01	35812
1992-01-01	36537
1993-01-01	37094
1994-01-01	38139
1995-01-01	38640
1996-01-01	39623
1997-01-01	40897
1998-01-01	42183
1999-01-01	43716
2000-01-01	45026
2001-01-01	45046
2002-01-01	45418
2003-01-01	46137
2004-01-01	47307
2005-01-01	48312
2006-01-01	49130
2007-01-01	49571
2008-01-01	48951
2009-01-01	47041
2010-01-01	47772
2011-01-01	48282