Year	US Dollars, Monthly Level
1969-01-01	1166580000000
1970-01-01	1474730000000
1971-01-01	1644310000000
1972-01-01	1797820000000
1973-01-01	2031580000000
1974-01-01	2168770000000
1975-01-01	2130790000000
1976-01-01	2356150000000
1977-01-01	2497810000000
1978-01-01	2674450000000
1979-01-01	2856700000000
1980-01-01	2993810000000
1981-01-01	3150670000000
1982-01-01	3177970000000
1983-01-01	3273340000000
1984-01-01	3594040000000
1985-01-01	3745240000000
1986-01-01	3860370000000
1987-01-01	4151170000000
1988-01-01	4468690000000
1989-01-01	4798800000000
1990-01-01	5143460000000
1991-01-01	5454350000000
1992-01-01	5892070000000
1993-01-01	6191010000000
1994-01-01	6805900000000
1995-01-01	7468980000000
1996-01-01	8013190000000
1997-01-01	8904820000000
1998-01-01	9324640000000
1999-01-01	9823840000000
2000-01-01	11090270000000
2001-01-01	11199030000000
2002-01-01	11687790000000
2003-01-01	12389190000000
2004-01-01	13727980000000
2005-01-01	14776790000000
2006-01-01	16161620000000
2007-01-01	17380250000000
2008-01-01	17887610000000
2009-01-01	16092070000000
2010-01-01	18032630000000
2011-01-01	19147480000000
2012-01-01	19726980000000
2013-01-01	20357480000000