Quarter	US dollars
1999-03-31	7110
1999-06-30	5529
1999-09-30	4935
1999-12-31	5231
2000-03-31	6017
2000-06-30	4736
2000-09-30	4068
2000-12-31	3395
2001-03-31	2918
2001-06-30	2915
2001-09-30	2850
2001-12-31	3857
2002-03-31	4782
2002-06-30	4198
2002-09-30	3322
2002-12-31	4785
2003-03-31	3406
2003-06-30	3329
2003-09-30	4595
2003-12-31	3436
2004-03-31	4340
2004-06-30	3747
2004-09-30	3121
2004-12-31	3447
2005-03-31	2336
2005-06-30	2338
2005-09-30	3104
2005-12-31	1745
2006-03-31	5043
2006-06-30	6138
2006-09-30	9673
2006-12-31	5115
2007-03-31	5087
2007-06-30	6706
2007-09-30	6268
2007-12-31	6900
2008-03-31	8388
2008-06-30	8781
2008-09-30	6800
2008-12-31	4936
2009-03-31	5941
2009-06-30	7321
2009-09-30	9239
2009-12-31	10753
2010-03-31	9961
2010-06-30	10858
2010-09-30	13438
2010-12-31	13259
2011-03-31	14473
2011-06-30	17195
2011-09-30	15735
2011-12-31	17271
2012-03-31	20785
2012-06-30	18361
2012-09-30	16316
2012-12-31	17736
2013-03-31	17729
2013-06-30	14467
2013-09-30	23727
2013-12-31	25249
2014-03-31	20636
2014-06-30	19768
2014-09-30	20577
2014-12-31	21275
2015-03-31	21737
2015-06-30	21087
2015-09-30	19916
2015-12-31	23472
2016-03-31	10368
2016-06-30	10945
2016-09-30	10101
2016-12-31	10232
2017-03-31	9994
2017-06-30	8170
2017-09-30	7878
2017-12-31	8096
2018-03-31	8349
2018-06-30	8220
2018-09-30	7184
2018-12-31	7670
2019-03-31	8584
2019-06-30	9655
2019-09-30	10504
2019-12-31	8809
2020-03-31	7638
2020-06-30	8094
2020-09-30	7460
2020-12-31	10006
2021-03-31	8949
2021-06-30	9153
2021-09-30	7919
2021-12-31	9205
2022-03-31	10208
2022-06-30	10339
2022-09-30	11087
2022-12-31	14916
2023-03-31	16333
2023-06-30	18972
2023-09-30	19688