Quarter	Millions of US Dollars
1997-07-01	30
1997-10-01	30
1998-01-01	30
1998-04-01	30
1998-07-01	30
1998-10-01	30
1999-01-01	30
1999-04-01	185
1999-07-01	190
1999-10-01	256
2000-01-01	245
2000-04-01	245
2000-07-01	197
2000-10-01	209
2001-01-01	199
2001-04-01	212
2001-07-01	228
2001-10-01	397
2002-01-01	393
2002-04-01	449
2002-07-01	463
2002-10-01	493
2003-01-01	512
2003-04-01	537
2003-07-01	548
2003-10-01	594
2004-01-01	575
2004-04-01	790
2004-07-01	807
2004-10-01	892
2005-01-01	849
2005-04-01	913
2005-07-01	885
2005-10-01	867
2006-01-01	890
2006-04-01	1189
2006-07-01	1184
2006-10-01	1225
2007-01-01	1239
2007-04-01	1215
2007-07-01	1276
2007-10-01	1325
2008-01-01	2056
2008-04-01	1892
2008-07-01	1716
2008-10-01	1392
2009-01-01	1331
2009-04-01	1413
2009-07-01	1464
2009-10-01	1441
2010-01-01	1348
2010-04-01	1227
2010-07-01	1365
2010-10-01	1336
2011-01-01	1421
2011-04-01	1656
2011-07-01	1580
2011-10-01	1535
2012-01-01	2568
2012-04-01	2507
2012-07-01	2534
2012-10-01	3806
2013-01-01	3774
2013-04-01	3796
2013-07-01	3830
2013-10-01	3853
2014-01-01	6611
2014-04-01	7394
2014-07-01	6367
2014-10-01	6265
2015-01-01	5888
2015-04-01	6005
2015-07-01	6570
2015-10-01	7066
2016-01-01	7254
2016-04-01	7980
2016-07-01	8007
2016-10-01	9149
2017-01-01	9092
2017-04-01	10983
2017-07-01	10930
2017-10-01	11091
2018-01-01	10839
2018-04-01	11486