Quarter	Millions of US Dollars
1979-01-01	30
1979-04-01	30
1979-07-01	32
1979-10-01	31
1980-01-01	27
1980-04-01	31
1980-07-01	30
1980-10-01	28
1981-01-01	26
1981-04-01	25
1981-07-01	25
1981-10-01	28
1982-01-01	26
1982-04-01	24
1982-07-01	23
1982-10-01	25
1983-01-01	24
1983-04-01	24
1983-07-01	24
1983-10-01	23
1984-01-01	23
1984-04-01	21
1984-07-01	20
1984-10-01	19
1985-01-01	19
1985-04-01	20
1985-07-01	23
1985-10-01	24
1986-01-01	26
1986-04-01	28
1986-07-01	30
1986-10-01	31
1994-01-01	179
1994-04-01	188
1994-07-01	194
1994-10-01	194
1995-01-01	217
1995-04-01	217
1995-07-01	211
1995-10-01	209
1996-01-01	203
1996-04-01	197
1996-07-01	196
1996-10-01	193
1997-01-01	179
1997-04-01	172
1997-07-01	170
1997-10-01	168
1998-01-01	163
1998-04-01	166
1998-07-01	179
1998-10-01	179
1999-01-01	165
1999-04-01	365
1999-07-01	1493
1999-10-01	1450
2000-01-01	2399
2000-04-01	3009
2000-07-01	3019
2000-10-01	4229
2001-01-01	5785
2001-04-01	5694
2001-07-01	7814
2001-10-01	10846
2002-01-01	13135
2002-04-01	17275
2002-07-01	20110
2002-10-01	24779
2003-01-01	30307
2003-04-01	37488
2003-07-01	39722
2003-10-01	46101
2004-01-01	50385
2004-04-01	51055
2004-07-01	53491
2004-10-01	63606
2005-01-01	66075
2005-04-01	70681
2005-07-01	72809
2005-10-01	79601
2006-01-01	94108
2006-04-01	103978
2006-07-01	109407
2006-10-01	114258
2007-01-01	122568
2007-04-01	128824
2007-07-01	135642
2007-10-01	141556
2008-01-01	150170
2008-04-01	154318
2008-07-01	140047
2008-10-01	135679
2009-01-01	131902
2009-04-01	138823
2009-07-01	139476
2009-10-01	141125
2010-01-01	129534
2010-04-01	113567
2010-07-01	131279
2010-10-01	127564
2011-01-01	132854
2011-04-01	138195
2011-07-01	124885
2011-10-01	117707
2012-01-01	106459
2012-04-01	101646
2012-07-01	105173
2012-10-01	108013
2013-01-01	101018
2013-04-01	99960
2013-07-01	99343
2013-10-01	100368
2014-01-01	95280
2014-04-01	92589
2014-07-01	87244
2014-10-01	87027
2015-01-01	76220
2015-04-01	81211
2015-07-01	81414
2015-10-01	74719
2016-01-01	77816
2016-04-01	61646
2016-07-01	63241
2016-10-01	61932
2017-01-01	62211
2017-04-01	61580
2017-07-01	69372
2017-10-01	77647
2018-01-01	82458
2018-04-01	81545