Year	Dollars
1976-01-01	3145000000
1977-01-01	2282000000
1978-01-01	2927000000
1979-01-01	3479000000
1980-01-01	2870000000
1981-01-01	-1486000000
1982-01-01	-5006000000
1983-01-01	-3681000000
1984-01-01	-3520000000
1985-01-01	-1476000000
1986-01-01	-4826000000
1987-01-01	-3318000000
1988-01-01	-10661000000
1989-01-01	-1796000000
1990-01-01	-8731000000
1991-01-01	-4183000000
1992-01-01	-1045000000
1993-01-01	2341000000
1994-01-01	-9065000000
1995-01-01	9260000000
1996-01-01	6673000000
1997-01-01	7410000000
1998-01-01	13282000000
1999-01-01	10462000000
2000-01-01	10221000000
2001-01-01	3173000000
2002-01-01	7180000000
2003-01-01	8686000000
2004-01-01	7997000000
2005-01-01	15180000000
2006-01-01	13261000000
2007-01-01	38067000000
2008-01-01	39039000000