Quarter	US dollars
1999-03-31	14194
1999-06-30	15683
1999-09-30	16955
1999-12-31	16034
2000-03-31	18959
2000-06-30	21884
2000-09-30	26421
2000-12-31	22552
2001-03-31	24227
2001-06-30	27144
2001-09-30	24013
2001-12-31	25615
2002-03-31	25400
2002-06-30	28687
2002-09-30	29635
2002-12-31	32612
2003-03-31	32787
2003-06-30	32973
2003-09-30	33720
2003-12-31	40676
2004-03-31	44773
2004-06-30	51664
2004-09-30	56073
2004-12-31	59939
2005-03-31	76497
2005-06-30	88260
2005-09-30	91349
2005-12-31	105701
2006-03-31	122221
2006-06-30	137028
2006-09-30	147512
2006-12-31	141490
2007-03-31	164117
2007-06-30	144084
2007-09-30	174471
2007-12-31	164635
2008-03-31	145328
2008-06-30	155308
2008-09-30	169932
2008-12-31	59538
2009-03-31	65837
2009-06-30	57239
2009-09-30	59673
2009-12-31	49618
2010-03-31	58789
2010-06-30	47035
2010-09-30	55985
2010-12-31	54584
2011-03-31	69956
2011-06-30	62297
2011-09-30	58417
2011-12-31	57451
2012-03-31	59057
2012-06-30	60221
2012-09-30	65626
2012-12-31	52141
2013-03-31	68339
2013-06-30	65714
2013-09-30	57659
2013-12-31	59095
2014-03-31	61175
2014-06-30	56729
2014-09-30	49369
2014-12-31	40417
2015-03-31	49496
2015-06-30	49446
2015-09-30	54971
2015-12-31	45019
2016-03-31	40146
2016-06-30	51707
2016-09-30	50226
2016-12-31	45907
2017-03-31	52722
2017-06-30	48502
2017-09-30	41748
2017-12-31	40672
2018-03-31	48700
2018-06-30	40370
2018-09-30	47800
2018-12-31	51465
2019-03-31	56664
2019-06-30	57382
2019-09-30	49813
2019-12-31	53880
2020-03-31	53791
2020-06-30	42710
2020-09-30	43036
2020-12-31	44488
2021-03-31	34060
2021-06-30	39210
2021-09-30	37588
2021-12-31	35468
2022-03-31	33135
2022-06-30	35046
2022-09-30	38100
2022-12-31	32303
2023-03-31	32501
2023-06-30	35669
2023-09-30	37285