Quarter	Millions of US Dollars
1988-04-01	75939
1988-07-01	76567
1988-10-01	87560
1989-01-01	80633
1989-04-01	72122
1989-07-01	77387
1989-10-01	85692
1990-01-01	82207
1990-04-01	79008
1990-07-01	87824
1990-10-01	90646
1991-01-01	92757
1991-04-01	89751
1991-07-01	102129
1991-10-01	107274
1992-01-01	107686
1992-04-01	110474
1992-07-01	110272
1992-10-01	114567
1993-01-01	123495
1993-04-01	121078
1993-07-01	128263
1993-10-01	141174
1994-01-01	142960
1994-04-01	141288
1994-07-01	142528
1994-10-01	156444
1995-01-01	148138
1995-04-01	154426
1995-07-01	163116
1995-10-01	161131
1996-01-01	163486
1996-04-01	161727
1996-07-01	167205
1996-10-01	169369
1997-01-01	164038
1997-04-01	155675
1997-07-01	153167
1997-10-01	134197
1998-01-01	134990
1998-04-01	120598
1998-07-01	119139
1998-10-01	120870
1999-01-01	121769
1999-04-01	121212
1999-07-01	118041
1999-10-01	113542
2000-01-01	104910
2000-04-01	99693
2000-07-01	90048
2000-10-01	90151
2001-01-01	79684
2001-04-01	78777
2001-07-01	79518
2001-10-01	78803
2002-01-01	80245
2002-04-01	84189
2002-07-01	88629
2002-10-01	89655
2003-01-01	93118
2003-04-01	100933
2003-07-01	102318
2003-10-01	110658
2004-01-01	114360
2004-04-01	102156
2004-07-01	105274
2004-10-01	117040
2005-01-01	116069
2005-04-01	115755
2005-07-01	115911
2005-10-01	114126
2006-01-01	115066
2006-04-01	112657
2006-07-01	117623
2006-10-01	121439
2007-01-01	124137
2007-04-01	133391
2007-07-01	145774
2007-10-01	146005
2008-01-01	153781
2008-04-01	166610
2008-07-01	150784
2008-10-01	141995
2009-01-01	157527
2009-04-01	211838
2009-07-01	237424
2009-10-01	260955
2010-01-01	287542
2010-04-01	294384
2010-07-01	346853
2010-10-01	376738
2011-01-01	409006
2011-04-01	435511
2011-07-01	442831
2011-10-01	488324
2012-01-01	519290
2012-04-01	525200
2012-07-01	564284
2012-10-01	575100
2013-01-01	587301
2013-04-01	508702
2013-07-01	537055
2013-10-01	525296
2014-01-01	563535
2014-04-01	594250
2014-07-01	574395
2014-10-01	568756
2015-01-01	554055
2015-04-01	541060
2015-07-01	525331
2015-10-01	540934
2016-01-01	596328
2016-04-01	582609
2016-07-01	617677
2016-10-01	576339
2017-01-01	626302
2017-04-01	641729
2017-07-01	649928
2017-10-01	664866
2018-01-01	658409