Quarter	Millions of US Dollars
1997-10-01	14923
1998-01-01	16276
1998-04-01	12171
1998-07-01	28539
1998-10-01	40869
1999-01-01	43458
1999-04-01	29938
1999-07-01	44434
1999-10-01	67238
2000-01-01	48153
2000-04-01	32784
2000-07-01	31746
2000-10-01	69745
2001-01-01	61249
2001-04-01	61285
2001-07-01	69825
2001-10-01	47639
2002-01-01	41829
2002-04-01	32590
2002-07-01	34151
2002-10-01	35807
2003-01-01	33555
2003-04-01	43349
2003-07-01	40324
2003-10-01	43487
2004-01-01	51125
2004-04-01	44417
2004-07-01	47744
2004-10-01	56071
2005-01-01	73062
2005-04-01	66413
2005-07-01	78991
2005-10-01	77530
2006-01-01	66989
2006-04-01	67360
2006-07-01	66009
2006-10-01	62776
2007-01-01	60697
2007-04-01	63253
2007-07-01	68859
2007-10-01	73547
2008-01-01	76374
2008-04-01	72094
2008-07-01	67538
2008-10-01	63469
2009-01-01	70799
2009-04-01	67068
2009-07-01	74273
2009-10-01	74675
2010-01-01	87041
2010-04-01	95793
2010-07-01	96660
2010-10-01	102705
2011-01-01	96963
2011-04-01	99582
2011-07-01	100265
2011-10-01	111052
2012-01-01	91100
2012-04-01	96544
2012-07-01	99235
2012-10-01	97016
2013-01-01	86580
2013-04-01	87633
2013-07-01	85002
2013-10-01	82560
2014-01-01	77824
2014-04-01	85233
2014-07-01	79960
2014-10-01	81166
2015-01-01	77831
2015-04-01	80993
2015-07-01	81853
2015-10-01	88612
2016-01-01	81856
2016-04-01	86668
2016-07-01	85828
2016-10-01	79779
2017-01-01	81877
2017-04-01	91170
2017-07-01	84030
2017-10-01	99837
2018-01-01	96952