Quarter	US dollars
1999-09-30	6386
1999-12-31	5964
2000-03-31	5234
2000-06-30	5215
2000-09-30	4511
2000-12-31	4273
2001-03-31	3621
2001-06-30	3619
2001-09-30	3540
2001-12-31	3158
2002-03-31	3047
2002-06-30	3216
2002-09-30	3267
2002-12-31	3459
2003-03-31	3377
2003-06-30	3485
2003-09-30	3908
2003-12-31	4202
2004-03-31	4263
2004-06-30	3977
2004-09-30	4176
2004-12-31	4397
2005-03-31	4281
2005-06-30	4376
2005-09-30	4735
2005-12-31	5126
2006-03-31	5806
2006-06-30	6120
2006-09-30	5978
2006-12-31	6341
2007-03-31	6601
2007-06-30	6489
2007-09-30	7412
2007-12-31	8344
2008-03-31	9312
2008-06-30	9279
2008-09-30	8823
2008-12-31	8628
2009-03-31	9142
2009-06-30	9322
2009-09-30	9933
2009-12-31	11012
2010-03-31	11127
2010-06-30	12409
2010-09-30	13037
2010-12-31	14067
2011-03-31	14354
2011-06-30	15018
2011-09-30	16160
2011-12-31	15272
2012-03-31	16584
2012-06-30	15945
2012-09-30	17716
2012-12-31	16534
2013-03-31	15943
2013-06-30	11890
2013-09-30	13232
2013-12-31	12015
2014-03-31	12886
2014-06-30	13117
2014-09-30	12135
2014-12-31	12030
2015-03-31	11842
2015-06-30	11679
2015-09-30	11124
2015-12-31	10594
2016-03-31	12333
2016-06-30	13170
2016-09-30	13197
2016-12-31	11544
2017-03-31	12420
2017-06-30	12393
2017-09-30	12800
2017-12-31	12879
2018-03-31	13207
2018-06-30	12485
2018-09-30	11879
2018-12-31	12809
2019-03-31	12926
2019-06-30	14086
2019-09-30	14776
2019-12-31	15193
2020-03-31	16042
2020-06-30	17775
2020-09-30	18860
2020-12-31	18941
2021-03-31	17003
2021-06-30	17618
2021-09-30	17533
2021-12-31	18176
2022-03-31	19349
2022-06-30	18049
2022-09-30	16699
2022-12-31	18139
2023-03-31	19721
2023-06-30	19108
2023-09-30	18564
2023-12-31	20599