Quarter	Millions of US Dollars
1999-10-01	28512
2000-01-01	27086
2000-04-01	27935
2000-07-01	26245
2000-10-01	27143
2001-01-01	24716
2001-04-01	22711
2001-07-01	24850
2001-10-01	23719
2002-01-01	22565
2002-04-01	25577
2002-07-01	25477
2002-10-01	24835
2003-01-01	23860
2003-04-01	24349
2003-07-01	25143
2003-10-01	25740
2004-01-01	24978
2004-04-01	24917
2004-07-01	25534
2004-10-01	27832
2005-01-01	24862
2005-04-01	22045
2005-07-01	22215
2005-10-01	20741
2006-01-01	20757
2006-04-01	22014
2006-07-01	22080
2006-10-01	21897
2007-01-01	21753
2007-04-01	21347
2007-07-01	23266
2007-10-01	24657
2008-01-01	26459
2008-04-01	26028
2008-07-01	24011
2008-10-01	25633
2009-01-01	24438
2009-04-01	27654
2009-07-01	33534
2009-10-01	34242
2010-01-01	34833
2010-04-01	35833
2010-07-01	40719
2010-10-01	43422
2011-01-01	44600
2011-04-01	51235
2011-07-01	48012
2011-10-01	47358
2012-01-01	51639
2012-04-01	49573
2012-07-01	52516
2012-10-01	53395
2013-01-01	52483
2013-04-01	55136
2013-07-01	56778
2013-10-01	58566
2014-01-01	58970
2014-04-01	58403
2014-07-01	56433
2014-10-01	55258
2015-01-01	60121
2015-04-01	63983
2015-07-01	60824
2015-10-01	60340
2016-01-01	62071
2016-04-01	60914
2016-07-01	61453
2016-10-01	58964
2017-01-01	60965
2017-04-01	65229
2017-07-01	65333
2017-10-01	66397
2018-01-01	69655