Quarter	Billions of US Dollars
1971-01-01	0.04
1971-04-01	0.08
1971-07-01	0.08
1971-10-01	0.08
1972-01-01	0.18
1972-04-01	0.28
1972-07-01	0.30
1972-10-01	0.33
1973-01-01	0.44
1973-04-01	0.48
1973-07-01	0.47
1973-10-01	0.44
1974-01-01	0.57
1974-04-01	0.60
1974-07-01	0.86
1974-10-01	1.06
1975-01-01	1.68
1975-04-01	2.17
1975-07-01	2.35
1975-10-01	2.84
1976-01-01	3.78
1976-04-01	4.73
1976-07-01	5.27
1976-10-01	5.87
1977-01-01	6.26
1977-04-01	6.63
1977-07-01	7.05
1977-10-01	8.09
1978-01-01	8.76
1978-04-01	9.18
1978-07-01	10.25
1978-10-01	10.27
1979-01-01	10.41
1979-04-01	11.08
1979-07-01	12.25
1979-10-01	12.71
1980-01-01	11.93
1980-04-01	13.26
1980-07-01	13.33
1980-10-01	13.65
1981-01-01	13.89
1981-04-01	13.45
1981-07-01	13.78
1981-10-01	14.67
1982-01-01	15.99
1982-04-01	17.43
1982-07-01	18.92
1982-10-01	20.98
1983-01-01	22.60
1983-04-01	23.96
1983-07-01	24.33
1983-10-01	25.46
1984-01-01	27.82
1984-04-01	27.86
1984-07-01	29.76
1984-10-01	30.78
1985-01-01	32.92
1985-04-01	33.57
1985-07-01	36.64
1985-10-01	37.49
1986-01-01	38.54
1986-04-01	41.50
1986-07-01	43.89
1986-10-01	45.32
1987-01-01	47.77
1987-04-01	48.47
1987-07-01	48.02
1987-10-01	52.47
1988-01-01	53.68
1988-04-01	54.12
1988-07-01	55.06
1988-10-01	57.72
1989-01-01	57.96
1989-04-01	57.64
1989-07-01	60.20
1989-10-01	63.42
1990-01-01	65.52
1990-04-01	68.65
1990-07-01	75.54
1990-10-01	78.55
1991-01-01	75.90
1991-04-01	78.46
1991-07-01	86.30
1991-10-01	98.22
1992-01-01	98.80
1992-04-01	108.73
1992-07-01	116.08
1992-10-01	111.70
1993-01-01	117.28
1993-04-01	119.19
1993-07-01	129.75
1993-10-01	131.54
1994-01-01	141.41
1994-04-01	146.96
1994-07-01	153.86
1994-10-01	155.05
1995-01-01	166.56
1995-04-01	167.88
1995-07-01	165.72
1995-10-01	169.34
1996-01-01	165.62
1996-04-01	165.00
1996-07-01	169.83
1996-10-01	170.00
1997-01-01	164.95
1997-04-01	164.85
1997-07-01	165.54
1997-10-01	163.93
1998-01-01	171.47
1998-04-01	177.46
1998-07-01	192.11
1998-10-01	199.20
1999-01-01	200.36
1999-04-01	210.15
1999-07-01	223.95
1999-10-01	228.31
2000-01-01	229.35
2000-04-01	242.13
2000-07-01	242.72
2000-10-01	264.99
2001-01-01	281.54
2001-04-01	289.15
2001-07-01	323.29
2001-10-01	336.86
2002-01-01	336.44
2002-04-01	394.73
2002-07-01	403.03
2002-10-01	436.93
2003-01-01	474.20
2003-04-01	527.88
2003-07-01	549.64
2003-10-01	611.76
2004-01-01	603.22
2004-04-01	614.40
2004-07-01	639.91
2004-10-01	732.31
2005-01-01	719.70
2005-04-01	711.55
2005-07-01	711.58
2005-10-01	735.74
2006-01-01	776.40
2006-04-01	839.47
2006-07-01	851.95
2006-10-01	952.27
2007-01-01	988.49
2007-04-01	1045.59
2007-07-01	1090.84
2007-10-01	1152.21
2008-01-01	1235.82
2008-04-01	1301.31
2008-07-01	1214.20
2008-10-01	1183.21
2009-01-01	1171.86
2009-04-01	1350.32
2009-07-01	1432.22
2009-10-01	1456.59
2010-01-01	1446.62
2010-04-01	1347.60
2010-07-01	1513.91
2010-10-01	1516.71
2011-01-01	1649.38
2011-04-01	1697.26
2011-07-01	1596.07
2011-10-01	1555.61
2012-01-01	1612.27
2012-04-01	1535.93
2012-07-01	1568.90
2012-10-01	1591.99
2013-01-01	1533.27
2013-04-01	1555.81
2013-07-01	1594.05
2013-10-01	1625.29
2014-01-01	1636.93
2014-04-01	1638.40
2014-07-01	1538.92
2014-10-01	1476.70
2015-01-01	1360.97
2015-04-01	1378.14