Quarter	US dollars
1999-03-31	4004
1999-06-30	3998
1999-09-30	4647
1999-12-31	4455
2000-03-31	4511
2000-06-30	4945
2000-09-30	5089
2000-12-31	4624
2001-03-31	4294
2001-06-30	2919
2001-09-30	4244
2001-12-31	4288
2002-03-31	4477
2002-06-30	4325
2002-09-30	4080
2002-12-31	4167
2003-03-31	3828
2003-06-30	3632
2003-09-30	3944
2003-12-31	3816
2004-03-31	4883
2004-06-30	5431
2004-09-30	5332
2004-12-31	6591
2005-03-31	7214
2005-06-30	5970
2005-09-30	5946
2005-12-31	7165
2006-03-31	9195
2006-06-30	8781
2006-09-30	12861
2006-12-31	15568
2007-03-31	15869
2007-06-30	16720
2007-09-30	19569
2007-12-31	20184
2008-03-31	19281
2008-06-30	21159
2008-09-30	18810
2008-12-31	15702
2009-03-31	14078
2009-06-30	15416
2009-09-30	17473
2009-12-31	16999
2010-03-31	16899
2010-06-30	16814
2010-09-30	18396
2010-12-31	18856
2011-03-31	20112
2011-06-30	21123
2011-09-30	17340
2011-12-31	16571
2012-03-31	16773
2012-06-30	19714
2012-09-30	20905
2012-12-31	21974
2013-03-31	19004
2013-06-30	17088
2013-09-30	14464
2013-12-31	14613
2014-03-31	11658
2014-06-30	12741
2014-09-30	11381
2014-12-31	12118
2015-03-31	10691
2015-06-30	9950
2015-09-30	10709
2015-12-31	11360
2016-03-31	12785
2016-06-30	12884
2016-09-30	13442
2016-12-31	11843
2017-03-31	11512
2017-06-30	11261
2017-09-30	10601
2017-12-31	10745
2018-03-31	11405
2018-06-30	10947
2018-09-30	11157
2018-12-31	10766
2019-03-31	11146
2019-06-30	10633
2019-09-30	10181
2019-12-31	9560
2020-03-31	9312
2020-06-30	8734
2020-09-30	8738
2020-12-31	9159
2021-03-31	8786
2021-06-30	8162
2021-09-30	8653
2021-12-31	8749
2022-03-31	8224
2022-06-30	7509
2022-09-30	7355
2022-12-31	7890
2023-03-31	8146
2023-06-30	8914
2023-09-30	8122