Year	2011 U.S. Dollars
1960-01-01	15320
1961-01-01	14849
1962-01-01	15397
1963-01-01	16018
1964-01-01	16737
1965-01-01	17200
1966-01-01	17398
1967-01-01	18268
1968-01-01	18942
1969-01-01	19847
1970-01-01	20732
1971-01-01	20571
1972-01-01	20675
1973-01-01	21305
1974-01-01	21313
1975-01-01	21509
1976-01-01	22090
1977-01-01	22226
1978-01-01	22469
1979-01-01	23085
1980-01-01	23495
1981-01-01	24096
1982-01-01	23700
1983-01-01	23295
1984-01-01	24436
1985-01-01	25448
1986-01-01	25676
1987-01-01	26529
1988-01-01	27228
1989-01-01	27965
1990-01-01	27967
1991-01-01	27373
1992-01-01	27750
1993-01-01	28593
1994-01-01	29630
1995-01-01	30264
1996-01-01	31067
1997-01-01	32025
1998-01-01	33261
1999-01-01	34255
2000-01-01	34910
2001-01-01	35303
2002-01-01	36256
2003-01-01	36963
2004-01-01	38017
2005-01-01	38677
2006-01-01	39169
2007-01-01	40357
2008-01-01	40644
2009-01-01	40447
2010-01-01	40910
2011-01-01	41340