Quarter	Billions of US Dollars
1966-01-01	0.08
1966-04-01	0.03
1966-07-01	0.02
1967-01-01	0.01
1967-04-01	0.11
1967-10-01	0.02
1968-01-01	0.30
1968-04-01	0.49
1968-07-01	0.17
1968-10-01	0.09
1969-01-01	0.23
1969-04-01	0.03
1969-07-01	0.03
1969-10-01	0.16
1970-01-01	0.03
1970-04-01	0.02
1970-07-01	0.08
1970-10-01	0.04
1971-01-01	0.83
1971-04-01	0.30
1971-07-01	0.24
1971-10-01	0.67
1972-01-01	1.59
1972-04-01	2.11
1972-07-01	1.53
1972-10-01	2.16
1973-01-01	1.67
1973-04-01	1.16
1973-07-01	1.17
1973-10-01	1.37
1974-01-01	1.00
1974-04-01	1.23
1974-07-01	1.60
1974-10-01	1.94
1975-01-01	3.58
1975-04-01	4.62
1975-07-01	2.81
1975-10-01	4.63
1976-01-01	7.13
1976-04-01	5.43
1976-07-01	4.63
1976-10-01	6.44
1977-01-01	5.90
1977-04-01	6.28
1977-07-01	5.12
1977-10-01	5.88
1978-01-01	6.58
1978-04-01	6.96
1978-07-01	4.76
1978-10-01	4.64
1979-01-01	8.05
1979-04-01	6.76
1979-07-01	6.19
1979-10-01	5.86
1980-01-01	5.53
1980-04-01	8.91
1980-07-01	6.36
1980-10-01	7.23
1981-01-01	7.24
1981-04-01	8.67
1981-07-01	8.46
1981-10-01	12.87
1982-01-01	18.04
1982-04-01	14.31
1982-07-01	14.30
1982-10-01	13.88
1983-01-01	16.94
1983-04-01	13.65
1983-07-01	9.43
1983-10-01	16.26
1984-01-01	23.21
1984-04-01	17.97
1984-07-01	19.60
1984-10-01	28.06
1985-01-01	29.44
1985-04-01	29.33
1985-07-01	27.34
1985-10-01	34.69
1986-01-01	41.72
1986-04-01	47.50
1986-07-01	47.05
1986-10-01	41.42
1987-01-01	46.60
1987-04-01	38.79
1987-07-01	33.75
1987-10-01	21.88
1988-01-01	45.86
1988-04-01	50.52
1988-07-01	47.91
1988-10-01	36.05
1989-01-01	62.99
1989-04-01	59.36
1989-07-01	44.72
1989-10-01	51.47
1990-01-01	51.74
1990-04-01	40.69
1990-07-01	51.02
1990-10-01	48.79
1991-01-01	71.82
1991-04-01	68.56
1991-07-01	59.28
1991-10-01	52.94
1992-01-01	74.27
1992-04-01	63.59
1992-07-01	57.65
1992-10-01	60.45
1993-01-01	104.83
1993-04-01	75.62
1993-07-01	96.59
1993-10-01	87.59
1994-01-01	108.35
1994-04-01	86.86
1994-07-01	97.08
1994-10-01	87.00
1995-01-01	96.55
1995-04-01	102.03
1995-07-01	113.18
1995-10-01	103.97
1996-01-01	162.28
1996-04-01	190.12
1996-07-01	193.46
1996-10-01	166.67
1997-01-01	185.48
1997-04-01	160.57
1997-07-01	177.10
1997-10-01	129.88
1998-01-01	214.21
1998-04-01	213.47
1998-07-01	160.92
1998-10-01	160.20
1999-01-01	284.59
1999-04-01	295.89
1999-07-01	283.71
1999-10-01	213.85
2000-01-01	287.81
2000-04-01	304.92
2000-07-01	318.38
2000-10-01	306.10
2001-01-01	496.99
2001-04-01	466.15
2001-07-01	313.01
2001-10-01	419.84
2002-01-01	418.50
2002-04-01	400.32
2002-07-01	288.36
2002-10-01	340.58
2003-01-01	523.04
2003-04-01	546.00
2003-07-01	468.40
2003-10-01	527.91
2004-01-01	684.04
2004-04-01	554.61
2004-07-01	532.22
2004-10-01	593.78
2005-01-01	698.91
2005-04-01	682.34
2005-07-01	551.74
2005-10-01	748.96
2006-01-01	838.76
2006-04-01	863.02
2006-07-01	813.97
2006-10-01	1079.59
2007-01-01	1129.24
2007-04-01	1204.29
2007-07-01	684.13
2007-10-01	690.78
2008-01-01	728.66
2008-04-01	1247.46
2008-07-01	764.38
2008-10-01	988.30
2009-01-01	979.98
2009-04-01	1011.90
2009-07-01	751.89
2009-10-01	699.60
2010-01-01	848.74
2010-04-01	580.58
2010-07-01	689.84
2010-10-01	585.05
2011-01-01	864.22
2011-04-01	742.81
2011-07-01	502.65
2011-10-01	558.35
2012-01-01	932.60
2012-04-01	569.91
2012-07-01	639.46
2012-10-01	605.72
2013-01-01	662.46
2013-04-01	645.27
2013-07-01	610.27
2013-10-01	716.58
2014-01-01	795.45
2014-04-01	877.88
2014-07-01	680.23
2014-10-01	580.15
2015-01-01	799.43
2015-04-01	646.08