Quarter	US dollars
1999-03-31	1846
1999-06-30	2181
1999-09-30	2509
1999-12-31	2700
2000-03-31	2668
2000-06-30	2421
2000-09-30	2387
2000-12-31	2399
2001-03-31	2544
2001-06-30	2572
2001-09-30	2553
2001-12-31	2504
2002-03-31	2407
2002-06-30	2702
2002-09-30	2655
2002-12-31	2993
2003-03-31	2890
2003-06-30	3157
2003-09-30	3061
2003-12-31	3533
2004-03-31	3527
2004-06-30	3794
2004-09-30	4116
2004-12-31	5723
2005-03-31	6942
2005-06-30	6557
2005-09-30	6167
2005-12-31	5252
2006-03-31	5867
2006-06-30	7013
2006-09-30	7013
2006-12-31	8237
2007-03-31	8475
2007-06-30	10534
2007-09-30	13363
2007-12-31	13294
2008-03-31	14577
2008-06-30	14131
2008-09-30	13239
2008-12-31	11161
2009-03-31	11205
2009-06-30	13142
2009-09-30	13656
2009-12-31	11855
2010-03-31	11228
2010-06-30	10192
2010-09-30	10761
2010-12-31	9892
2011-03-31	10085
2011-06-30	9690
2011-09-30	8867
2011-12-31	8355
2012-03-31	8280
2012-06-30	8174
2012-09-30	8216
2012-12-31	7636
2013-03-31	7158
2013-06-30	6528
2013-09-30	6946
2013-12-31	7167
2014-03-31	7264
2014-06-30	8042
2014-09-30	6707
2014-12-31	6710
2015-03-31	6602
2015-06-30	6858
2015-09-30	7322
2015-12-31	7447
2016-03-31	7507
2016-06-30	7412
2016-09-30	7227
2016-12-31	7357
2017-03-31	7431
2017-06-30	8000
2017-09-30	8047
2017-12-31	7799
2018-03-31	9230
2018-06-30	7202
2018-09-30	6461
2018-12-31	5657
2019-03-31	5920
2019-06-30	5856
2019-09-30	5652
2019-12-31	5736
2020-03-31	6375
2020-06-30	6182
2020-09-30	5965
2020-12-31	5553
2021-03-31	6186
2021-06-30	6221
2021-09-30	6099
2021-12-31	5587
2022-03-31	4780
2022-06-30	4425
2022-09-30	4052
2022-12-31	4023
2023-03-31	4182
2023-06-30	4405
2023-09-30	4188