Quarter	Billions of US Dollars
1968-01-01	0.060
1968-04-01	0.060
1972-01-01	0.047
1972-04-01	0.103
1972-10-01	0.030
1973-01-01	0.037
1973-10-01	0.098
1974-01-01	0.043
1974-07-01	0.044
1974-10-01	0.023
1975-01-01	0.088
1975-04-01	0.069
1975-07-01	0.092
1975-10-01	0.029
1976-01-01	0.067
1976-04-01	0.109
1976-07-01	0.031
1976-10-01	0.099
1977-01-01	0.035
1977-04-01	0.342
1977-07-01	0.033
1977-10-01	0.011
1978-01-01	0.166
1978-04-01	0.202
1978-07-01	0.119
1978-10-01	0.100
1979-01-01	0.092
1979-04-01	0.125
1979-07-01	0.062
1980-04-01	0.025
1980-07-01	0.086
1980-10-01	0.108
1981-04-01	0.160
1981-07-01	0.092
1981-10-01	0.014
1982-01-01	0.232
1982-04-01	0.235
1982-07-01	0.523
1982-10-01	0.546
1983-01-01	1.218
1983-04-01	0.698
1983-07-01	0.092
1983-10-01	0.841
1984-01-01	0.988
1984-04-01	0.249
1984-07-01	0.440
1984-10-01	0.824
1985-01-01	0.447
1985-04-01	0.747
1985-07-01	0.943
1985-10-01	1.313
1986-01-01	1.978
1986-04-01	3.563
1986-07-01	2.375
1986-10-01	2.224
1987-01-01	4.154
1987-04-01	1.480
1987-07-01	2.885
1987-10-01	1.057
1988-01-01	3.127
1988-04-01	1.635
1988-07-01	2.938
1988-10-01	3.550
1989-01-01	1.378
1989-04-01	2.822
1989-07-01	2.298
1989-10-01	2.580
1990-01-01	3.310
1990-04-01	1.359
1990-07-01	2.297
1990-10-01	1.101
1991-01-01	2.853
1991-04-01	3.542
1991-07-01	3.880
1991-10-01	4.546
1992-01-01	5.541
1992-04-01	5.698
1992-07-01	4.939
1992-10-01	3.783
1993-01-01	13.474
1993-04-01	7.017
1993-07-01	8.351
1993-10-01	10.650
1994-01-01	15.464
1994-04-01	7.552
1994-07-01	10.675
1994-10-01	12.090
1995-01-01	15.737
1995-04-01	17.901
1995-07-01	16.457
1995-10-01	15.299
1996-01-01	26.234
1996-04-01	22.219
1996-07-01	20.390
1996-10-01	24.675
1997-01-01	37.012
1997-04-01	23.154
1997-07-01	22.259
1997-10-01	14.322
1998-01-01	35.823
1998-04-01	33.152
1998-07-01	21.848
1998-10-01	20.068
1999-01-01	47.568
1999-04-01	38.592
1999-07-01	47.153
1999-10-01	30.006
2000-01-01	51.728
2000-04-01	53.802
2000-07-01	41.109
2000-10-01	53.616
2001-01-01	74.588
2001-04-01	61.282
2001-07-01	53.027
2001-10-01	60.379
2002-01-01	68.190
2002-04-01	68.234
2002-07-01	51.271
2002-10-01	59.403
2003-01-01	83.902
2003-04-01	100.819
2003-07-01	72.731
2003-10-01	68.196
2004-01-01	122.973
2004-04-01	84.423
2004-07-01	97.325
2004-10-01	81.148
2005-01-01	128.720
2005-04-01	129.745
2005-07-01	70.951
2005-10-01	98.619
2006-01-01	126.885
2006-04-01	105.064
2006-07-01	105.996
2006-10-01	104.713
2007-01-01	113.933
2007-04-01	109.976
2007-07-01	78.511
2007-10-01	74.106
2008-01-01	112.316
2008-04-01	117.956
2008-07-01	65.689
2008-10-01	101.617
2009-01-01	135.302
2009-04-01	85.726
2009-07-01	71.365
2009-10-01	50.617
2010-01-01	103.691
2010-04-01	58.066
2010-07-01	71.927
2010-10-01	39.978
2011-01-01	108.898
2011-04-01	71.506
2011-07-01	77.604
2011-10-01	42.470
2012-01-01	136.263
2012-04-01	73.997
2012-07-01	67.570
2012-10-01	73.004
2013-01-01	87.450
2013-04-01	72.940
2013-07-01	66.360
2013-10-01	58.568
2014-01-01	95.191
2014-04-01	100.778
2014-07-01	67.183
2014-10-01	79.335
2015-01-01	89.434
2015-04-01	77.040