Quarter	US dollars
1999-03-31	20382
1999-06-30	18612
1999-09-30	16721
1999-12-31	14737
2000-03-31	17330
2000-06-30	15879
2000-09-30	12164
2000-12-31	14650
2001-03-31	16403
2001-06-30	14662
2001-09-30	15793
2001-12-31	16066
2002-03-31	17654
2002-06-30	14733
2002-09-30	14957
2002-12-31	16270
2003-03-31	15226
2003-06-30	12265
2003-09-30	13467
2003-12-31	18853
2004-03-31	21191
2004-06-30	19928
2004-09-30	20773
2004-12-31	23670
2005-03-31	24841
2005-06-30	18856
2005-09-30	23261
2005-12-31	21321
2006-03-31	26340
2006-06-30	34411
2006-09-30	27206
2006-12-31	34569
2007-03-31	33189
2007-06-30	33290
2007-09-30	40302
2007-12-31	43934
2008-03-31	44288
2008-06-30	35103
2008-09-30	41666
2008-12-31	29372
2009-03-31	32813
2009-06-30	30167
2009-09-30	25438
2009-12-31	24917
2010-03-31	26075
2010-06-30	32255
2010-09-30	30521
2010-12-31	23888
2011-03-31	28946
2011-06-30	26825
2011-09-30	34542
2011-12-31	30615
2012-03-31	33581
2012-06-30	31771
2012-09-30	37032
2012-12-31	30604
2013-03-31	30498
2013-06-30	31280
2013-09-30	29989
2013-12-31	26133
2014-03-31	25136
2014-06-30	26072
2014-09-30	27844
2014-12-31	28181
2015-03-31	27317
2015-06-30	28940
2015-09-30	30484
2015-12-31	26488
2016-03-31	23430
2016-06-30	25311
2016-09-30	30377
2016-12-31	21597
2017-03-31	18950
2017-06-30	19638
2017-09-30	22105
2017-12-31	19969
2018-03-31	25172
2018-06-30	23662
2018-09-30	22633
2018-12-31	20192
2019-03-31	19473
2019-06-30	18622
2019-09-30	21034
2019-12-31	17264
2020-03-31	18236
2020-06-30	16567
2020-09-30	18781
2020-12-31	20909
2021-03-31	21389
2021-06-30	22881
2021-09-30	26239
2021-12-31	25148
2022-03-31	22341
2022-06-30	19746
2022-09-30	19490
2022-12-31	18213
2023-03-31	23466
2023-06-30	20669
2023-09-30	16014