Quarter	US dollars
1999-03-31	3451
1999-06-30	2712
1999-09-30	2792
1999-12-31	4628
2000-03-31	2156
2000-06-30	3344
2000-09-30	4889
2000-12-31	6832
2001-03-31	4810
2001-06-30	3395
2001-09-30	6013
2001-12-31	4490
2002-03-31	4070
2002-06-30	4695
2002-09-30	7116
2002-12-31	8673
2003-03-31	13441
2003-06-30	14826
2003-09-30	16117
2003-12-31	13276
2004-03-31	10681
2004-06-30	19947
2004-09-30	16561
2004-12-31	17004
2005-03-31	24562
2005-06-30	19537
2005-09-30	32165
2005-12-31	39332
2006-03-31	34479
2006-06-30	47197
2006-09-30	37549
2006-12-31	45367
2007-03-31	48460
2007-06-30	54014
2007-09-30	47839
2007-12-31	53744
2008-03-31	43298
2008-06-30	45189
2008-09-30	37880
2008-12-31	32339
2009-03-31	30590
2009-06-30	16062
2009-09-30	18781
2009-12-31	19883
2010-03-31	22011
2010-06-30	18802
2010-09-30	19888
2010-12-31	21127
2011-03-31	21590
2011-06-30	19807
2011-09-30	20046
2011-12-31	14146
2012-03-31	17985
2012-06-30	18088
2012-09-30	13522
2012-12-31	14276
2013-03-31	18837
2013-06-30	15128
2013-09-30	17583
2013-12-31	14922
2014-03-31	12875
2014-06-30	13976
2014-09-30	10191
2014-12-31	18517
2015-03-31	13558
2015-06-30	21896
2015-09-30	21518
2015-12-31	19996
2016-03-31	19250
2016-06-30	20479
2016-09-30	21104
2016-12-31	20546
2017-03-31	26299
2017-06-30	22823
2017-09-30	25402
2017-12-31	31499
2018-03-31	27894
2018-06-30	23008
2018-09-30	22175
2018-12-31	26065
2019-03-31	24323
2019-06-30	23313
2019-09-30	22415
2019-12-31	25962
2020-03-31	27932
2020-06-30	27568
2020-09-30	22994
2020-12-31	23229
2021-03-31	22429
2021-06-30	21887
2021-09-30	21693
2021-12-31	25088
2022-03-31	24496
2022-06-30	22563
2022-09-30	29043
2022-12-31	30485
2023-03-31	30649
2023-06-30	28048
2023-09-30	30781