Quarter	Billions of US Dollars
1968-01-01	0.06
1968-04-01	0.12
1968-07-01	0.12
1968-10-01	0.12
1969-01-01	0.12
1969-04-01	0.12
1969-07-01	0.12
1969-10-01	0.12
1970-01-01	0.12
1970-04-01	0.12
1970-07-01	0.12
1970-10-01	0.12
1971-01-01	0.12
1971-04-01	0.12
1971-07-01	0.12
1971-10-01	0.12
1972-01-01	0.17
1972-04-01	0.27
1972-07-01	0.27
1972-10-01	0.30
1973-01-01	0.36
1973-04-01	0.37
1973-07-01	0.37
1973-10-01	0.45
1974-01-01	0.49
1974-04-01	0.51
1974-07-01	0.55
1974-10-01	0.62
1975-01-01	0.72
1975-04-01	0.78
1975-07-01	0.82
1975-10-01	0.87
1976-01-01	0.96
1976-04-01	1.07
1976-07-01	1.11
1976-10-01	1.22
1977-01-01	1.23
1977-04-01	1.59
1977-07-01	1.70
1977-10-01	1.83
1978-01-01	2.07
1978-04-01	2.27
1978-07-01	2.61
1978-10-01	2.68
1979-01-01	2.68
1979-04-01	2.77
1979-07-01	2.93
1979-10-01	2.90
1980-01-01	2.64
1980-04-01	2.85
1980-07-01	2.88
1980-10-01	2.81
1981-01-01	2.66
1981-04-01	2.61
1981-07-01	2.76
1981-10-01	2.89
1982-01-01	2.86
1982-04-01	2.80
1982-07-01	3.24
1982-10-01	3.75
1983-01-01	4.71
1983-04-01	5.37
1983-07-01	5.34
1983-10-01	6.08
1984-01-01	7.02
1984-04-01	7.07
1984-07-01	7.39
1984-10-01	7.85
1985-01-01	8.39
1985-04-01	9.02
1985-07-01	10.42
1985-10-01	11.58
1986-01-01	13.68
1986-04-01	17.72
1986-07-01	20.74
1986-10-01	23.24
1987-01-01	27.63
1987-04-01	29.27
1987-07-01	31.48
1987-10-01	35.23
1988-01-01	36.45
1988-04-01	36.74
1988-07-01	38.20
1988-10-01	42.30
1989-01-01	42.19
1989-04-01	43.72
1989-07-01	46.54
1989-10-01	50.50
1990-01-01	52.46
1990-04-01	54.80
1990-07-01	59.34
1990-10-01	60.78
1991-01-01	56.65
1991-04-01	56.47
1991-07-01	61.56
1991-10-01	70.02
1992-01-01	68.60
1992-04-01	76.57
1992-07-01	83.07
1992-10-01	78.52
1993-01-01	84.25
1993-04-01	89.91
1993-07-01	97.16
1993-10-01	100.72
1994-01-01	115.37
1994-04-01	124.24
1994-07-01	134.15
1994-10-01	144.47
1995-01-01	165.90
1995-04-01	180.70
1995-07-01	189.13
1995-10-01	201.75
1996-01-01	217.81
1996-04-01	228.59
1996-07-01	242.84
1996-10-01	259.84
1997-01-01	271.78
1997-04-01	288.71
1997-07-01	298.56
1997-10-01	301.70
1998-01-01	320.24
1998-04-01	344.16
1998-07-01	376.30
1998-10-01	381.00
1999-01-01	391.71
1999-04-01	407.74
1999-07-01	457.67
1999-10-01	452.55
2000-01-01	470.81
2000-04-01	496.62
2000-07-01	509.14
2000-10-01	556.01
2001-01-01	584.04
2001-04-01	608.08
2001-07-01	666.61
2001-10-01	675.37
2002-01-01	708.19
2002-04-01	824.26
2002-07-01	842.25
2002-10-01	902.82
2003-01-01	951.72
2003-04-01	1029.44
2003-07-01	1081.39
2003-10-01	1181.65
2004-01-01	1207.48
2004-04-01	1239.65
2004-07-01	1320.37
2004-10-01	1460.37
2005-01-01	1464.71
2005-04-01	1448.74
2005-07-01	1443.66
2005-10-01	1465.32
2006-01-01	1553.19
2006-04-01	1672.14
2006-07-01	1718.59
2006-10-01	1825.10
2007-01-01	1880.11
2007-04-01	1943.97
2007-07-01	2012.97
2007-10-01	2068.61
2008-01-01	2187.68
2008-04-01	2208.53
2008-07-01	2029.02
2008-10-01	2014.89
2009-01-01	1949.63
2009-04-01	2072.92
2009-07-01	2111.70
2009-10-01	2072.83
2010-01-01	1969.82
2010-04-01	1826.12
2010-07-01	1979.46
2010-10-01	1917.55
2011-01-01	1979.40
2011-04-01	2008.80
2011-07-01	1909.03
2011-10-01	1868.08
2012-01-01	1930.48
2012-04-01	1854.61
2012-07-01	1887.59
2012-10-01	1922.74
2013-01-01	1855.98
2013-04-01	1856.35
2013-07-01	1874.91
2013-10-01	1901.05
2014-01-01	1879.51
2014-04-01	1887.03
2014-07-01	1776.84
2014-10-01	1739.44
2015-01-01	1594.47
2015-04-01	1648.86