Year	US Dollars, Sum Over Component Sub-periods
1981-01-01	449000000
1982-01-01	504000000
1983-01-01	546000000
1984-01-01	570000000
1985-01-01	844000000
1986-01-01	844000000
1987-01-01	1065000000
1988-01-01	1369000000
1989-01-01	1875000000
1990-01-01	2488000000
1991-01-01	2822000000
1992-01-01	3391000000
1993-01-01	3959000000
1994-01-01	4797000000
1995-01-01	5469000000
1996-01-01	6599000000
1997-01-01	6941000000
1998-01-01	4479000000
1999-01-01	4599000000
2000-01-01	5214000000
2001-01-01	5500000000
2002-01-01	6663000000
2003-01-01	5293000000
2004-01-01	12045000000
2005-01-01	12926000000
2006-01-01	11520000000
2007-01-01	12487000000
2008-01-01	15247000000
2009-01-01	13155000000
2010-01-01	16766000000
2011-01-01	20691000000
2012-01-01	23114000000
2013-01-01	22562000000