Quarter	Millions of US Dollars
1968-07-01	0
1968-10-01	0
1969-01-01	0
1969-04-01	0
1969-07-01	0
1969-10-01	0
1970-01-01	0
1970-04-01	0
1970-07-01	0
1970-10-01	0
1971-01-01	0
1971-04-01	0
1971-07-01	0
1971-10-01	0
1972-01-01	0
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
1977-01-01	0
1977-04-01	0
1977-07-01	30
1977-10-01	85
1978-01-01	114
1978-04-01	175
1978-07-01	184
1978-10-01	203
1979-01-01	394
1979-04-01	553
1979-07-01	628
1979-10-01	739
1980-01-01	620
1980-04-01	735
1980-07-01	764
1980-10-01	696
1981-01-01	726
1981-04-01	990
1981-07-01	1400
1981-10-01	1449
1982-01-01	1860
1982-04-01	1626
1982-07-01	1362
1982-10-01	1734
1983-01-01	1583
1983-04-01	1765
1983-07-01	2071
1983-10-01	1943
1984-01-01	1839
1984-04-01	1637
1984-07-01	1598
1984-10-01	3621
1985-01-01	3797
1985-04-01	4040
1985-07-01	4264
1985-10-01	2624
1986-01-01	2966
1986-04-01	2881
1986-07-01	3111
1986-10-01	3238
1987-01-01	3705
1987-04-01	4758
1987-07-01	5276
1987-10-01	5783
1988-01-01	5505
1988-04-01	4664
1988-07-01	4133
1988-10-01	3937
1989-01-01	3391
1989-04-01	4121
1989-07-01	4572
1989-10-01	5211
1990-01-01	6112
1990-04-01	4801
1990-07-01	4289
1990-10-01	3728
1991-01-01	3369
1991-04-01	3804
1991-07-01	4367
1991-10-01	6699
1992-01-01	7018
1992-04-01	8028
1992-07-01	10533
1992-10-01	10429
1993-01-01	9785
1993-04-01	9954
1993-07-01	18122
1993-10-01	18081
1994-01-01	21511
1994-04-01	23884
1994-07-01	26146
1994-10-01	26119
1995-01-01	23052
1995-04-01	27430
1995-07-01	33355
1995-10-01	36515
1996-01-01	37749
1996-04-01	40026
1996-07-01	38453
1996-10-01	46157
1997-01-01	46289
1997-04-01	48166
1997-07-01	46242
1997-10-01	66229
1998-01-01	69258
1998-04-01	71831
1998-07-01	68284
1998-10-01	46651
1999-01-01	45672
1999-04-01	54310
1999-07-01	59379
1999-10-01	59242
2000-01-01	63428
2000-04-01	92800
2000-07-01	93474
2000-10-01	103337
2001-01-01	103201
2001-04-01	72311
2001-07-01	71005
2001-10-01	65759
2002-01-01	71548
2002-04-01	79009
2002-07-01	81042
2002-10-01	84050
2003-01-01	85133
2003-04-01	83427
2003-07-01	86722
2003-10-01	87812
2004-01-01	81640
2004-04-01	115387
2004-07-01	122373
2004-10-01	126831
2005-01-01	125740
2005-04-01	98186
2005-07-01	85794
2005-10-01	89824
2006-01-01	97212
2006-04-01	88144
2006-07-01	104774
2006-10-01	104047
2007-01-01	118343
2007-04-01	121289
2007-07-01	109171
2007-10-01	123364
2008-01-01	131978
2008-04-01	139596
2008-07-01	137706
2008-10-01	127303
2009-01-01	124903
2009-04-01	129243
2009-07-01	139783
2009-10-01	136037
2010-01-01	127983
2010-04-01	131204
2010-07-01	145040
2010-10-01	141258
2011-01-01	155092
2011-04-01	162686
2011-07-01	154738
2011-10-01	175252
2012-01-01	195337
2012-04-01	195046
2012-07-01	207861
2012-10-01	208156
2013-01-01	232746
2013-04-01	271614
2013-07-01	300729
2013-10-01	323716
2014-01-01	344934
2014-04-01	333547
2014-07-01	338466
2014-10-01	370068
2015-01-01	355377
2015-04-01	372874
2015-07-01	367780
2015-10-01	354632
2016-01-01	377283
2016-04-01	437401
2016-07-01	436987
2016-10-01	457119
2017-01-01	477182
2017-04-01	480832
2017-07-01	481005
2017-10-01	484360
2018-01-01	461037
2018-04-01	466152