Quarter	Millions of US Dollars
1999-01-01	2499
1999-04-01	2705
1999-07-01	2603
1999-10-01	2775
2000-01-01	2706
2000-04-01	2670
2000-07-01	2604
2000-10-01	2432
2001-01-01	2258
2001-04-01	2359
2001-07-01	2226
2001-10-01	2217
2002-01-01	2350
2002-04-01	2474
2002-07-01	2384
2002-10-01	2454
2003-01-01	2474
2003-04-01	2929
2003-07-01	2904
2003-10-01	3274
2004-01-01	3479
2004-04-01	4461
2004-07-01	4826
2004-10-01	5388
2005-01-01	6572
2005-04-01	8664
2005-07-01	9745
2005-10-01	9888
2006-01-01	10759
2006-04-01	12648
2006-07-01	14629
2006-10-01	15813
2007-01-01	17973
2007-04-01	23111
2007-07-01	26407
2007-10-01	29942
2008-01-01	33451
2008-04-01	37378
2008-07-01	32292
2008-10-01	23415
2009-01-01	24754
2009-04-01	31537
2009-07-01	35227
2009-10-01	36787
2010-01-01	39837
2010-04-01	38231
2010-07-01	43215
2010-10-01	45338
2011-01-01	46909
2011-04-01	46562
2011-07-01	41331
2011-10-01	38928
2012-01-01	41588
2012-04-01	36776
2012-07-01	38564
2012-10-01	42122
2013-01-01	44442
2013-04-01	44777
2013-07-01	47108
2013-10-01	47779
2014-01-01	47855
2014-04-01	48548
2014-07-01	46339
2014-10-01	39993
2015-01-01	39644
2015-04-01	40984
2015-07-01	39667
2015-10-01	39775
2016-01-01	41226
2016-04-01	41959
2016-07-01	46552
2016-10-01	46144
2017-01-01	50972
2017-04-01	55236
2017-07-01	56509
2017-10-01	58398
2018-01-01	59621