Quarter	Millions of US Dollars
2010-01-01	0
2010-04-01	0
2010-07-01	260890
2010-10-01	232428
2011-01-01	256088
2011-04-01	250193
2011-07-01	238997
2011-10-01	240634
2012-01-01	245551
2012-04-01	227387
2012-07-01	248939
2012-10-01	249003
2013-01-01	248379
2013-04-01	233749
2013-07-01	250892
2013-10-01	257535
2014-01-01	263031
2014-04-01	243090
2014-07-01	235264
2014-10-01	228073
2015-01-01	209776
2015-04-01	215308
2015-07-01	215341
2015-10-01	216151
2016-01-01	241078
2016-04-01	225748
2016-07-01	225054
2016-10-01	213088
2017-01-01	227562
2017-04-01	232686
2017-07-01	244074
2017-10-01	245590
2018-01-01	244620