Quarter	Millions of US Dollars
1988-04-01	151929
1988-07-01	155602
1988-10-01	173773
1989-01-01	170636
1989-04-01	161036
1989-07-01	173004
1989-10-01	183000
1990-01-01	175331
1990-04-01	178645
1990-07-01	196394
1990-10-01	188564
1991-01-01	195976
1991-04-01	191774
1991-07-01	205130
1991-10-01	201201
1992-01-01	204679
1992-04-01	203069
1992-07-01	195328
1992-10-01	193740
1993-01-01	202114
1993-04-01	188479
1993-07-01	185442
1993-10-01	199934
1994-01-01	206758
1994-04-01	210234
1994-07-01	214318
1994-10-01	231049
1995-01-01	219026
1995-04-01	217280
1995-07-01	234630
1995-10-01	237702
1996-01-01	252768
1996-04-01	255719
1996-07-01	262531
1996-10-01	273083
1997-01-01	264069
1997-04-01	256680
1997-07-01	254514
1997-10-01	229889
1998-01-01	234334
1998-04-01	221703
1998-07-01	220956
1998-10-01	232168
1999-01-01	244006
1999-04-01	257506
1999-07-01	259573
1999-10-01	262804
2000-01-01	249566
2000-04-01	248148
2000-07-01	223262
2000-10-01	228748
2001-01-01	204893
2001-04-01	211412
2001-07-01	209706
2001-10-01	222089
2002-01-01	235261
2002-04-01	252975
2002-07-01	257584
2002-10-01	263375
2003-01-01	284325
2003-04-01	324585
2003-07-01	331965
2003-10-01	378447
2004-01-01	400371
2004-04-01	367883
2004-07-01	394073
2004-10-01	443264
2005-01-01	456692
2005-04-01	459770
2005-07-01	460959
2005-10-01	463116
2006-01-01	465358
2006-04-01	499988
2006-07-01	517982
2006-10-01	559209
2007-01-01	583643
2007-04-01	647553
2007-07-01	756340
2007-10-01	800240
2008-01-01	860410
2008-04-01	944093
2008-07-01	805156
2008-10-01	743425
2009-01-01	738283
2009-04-01	887780
2009-07-01	970328
2009-10-01	1003708
2010-01-01	1016545
2010-04-01	962553
2010-07-01	1105206
2010-10-01	1187176
2011-01-01	1223693
2011-04-01	1286791
2011-07-01	1231622
2011-10-01	1307753
2012-01-01	1405041
2012-04-01	1392433
2012-07-01	1461825
2012-10-01	1444518
2013-01-01	1447329
2013-04-01	1287340
2013-07-01	1317494
2013-10-01	1285967
2014-01-01	1365316
2014-04-01	1435730
2014-07-01	1377678
2014-10-01	1349176
2015-01-01	1288198
2015-04-01	1288991
2015-07-01	1211615
2015-10-01	1257639
2016-01-01	1360294
2016-04-01	1324046
2016-07-01	1378173
2016-10-01	1284847
2017-01-01	1386964
2017-04-01	1396878
2017-07-01	1414642
2017-10-01	1432705
2018-01-01	1422471