Quarter	US dollars
1999-03-31	4841
1999-06-30	4756
1999-09-30	5290
1999-12-31	4669
2000-03-31	4518
2000-06-30	5567
2000-09-30	7404
2000-12-31	6017
2001-03-31	7901
2001-06-30	4931
2001-09-30	4668
2001-12-31	4766
2002-03-31	4286
2002-06-30	4564
2002-09-30	4157
2002-12-31	4239
2003-03-31	4178
2003-06-30	5528
2003-09-30	4382
2003-12-31	4503
2004-03-31	6291
2004-06-30	5683
2004-09-30	4716
2004-12-31	5943
2005-03-31	6665
2005-06-30	6209
2005-09-30	5655
2005-12-31	4310
2006-03-31	5692
2006-06-30	8357
2006-09-30	11428
2006-12-31	15613
2007-03-31	16893
2007-06-30	17474
2007-09-30	24762
2007-12-31	15651
2008-03-31	21315
2008-06-30	17334
2008-09-30	8676
2008-12-31	9898
2009-03-31	9939
2009-06-30	8015
2009-09-30	7541
2009-12-31	7881
2010-03-31	8871
2010-06-30	9487
2010-09-30	8677
2010-12-31	9297
2011-03-31	15329
2011-06-30	11012
2011-09-30	11517
2011-12-31	7616
2012-03-31	10731
2012-06-30	9348
2012-09-30	10307
2012-12-31	9596
2013-03-31	9039
2013-06-30	9281
2013-09-30	10017
2013-12-31	8267
2014-03-31	8924
2014-06-30	9139
2014-09-30	10224
2014-12-31	11059
2015-03-31	11678
2015-06-30	9302
2015-09-30	10846
2015-12-31	10065
2016-03-31	10585
2016-06-30	11736
2016-09-30	11150
2016-12-31	9000
2017-03-31	9373
2017-06-30	9260
2017-09-30	9177
2017-12-31	9077
2018-03-31	9169
2018-06-30	8682
2018-09-30	8583
2018-12-31	9992
2019-03-31	10418
2019-06-30	10507
2019-09-30	11290
2019-12-31	11639
2020-03-31	10838
2020-06-30	10706
2020-09-30	10889
2020-12-31	9593
2021-03-31	8991
2021-06-30	8805
2021-09-30	8182
2021-12-31	6915
2022-03-31	6947
2022-06-30	6459
2022-09-30	7588
2022-12-31	6388
2023-03-31	6220
2023-06-30	6050
2023-09-30	6054