Quarter	US dollars
1999-03-31	2519
1999-06-30	2410
1999-09-30	2477
1999-12-31	2362
2000-03-31	2580
2000-06-30	2381
2000-09-30	2430
2000-12-31	3427
2001-03-31	4160
2001-06-30	3961
2001-09-30	3815
2001-12-31	4157
2002-03-31	4694
2002-06-30	4638
2002-09-30	4237
2002-12-31	2659
2003-03-31	2715
2003-06-30	2356
2003-09-30	2462
2003-12-31	2865
2004-03-31	2667
2004-06-30	2706
2004-09-30	2881
2004-12-31	3198
2005-03-31	3100
2005-06-30	4327
2005-09-30	3454
2005-12-31	4503
2006-03-31	4314
2006-06-30	4292
2006-09-30	4819
2006-12-31	5686
2007-03-31	5391
2007-06-30	6117
2007-09-30	6803
2007-12-31	6076
2008-03-31	6041
2008-06-30	5400
2008-09-30	5082
2008-12-31	4627
2009-03-31	5239
2009-06-30	4447
2009-09-30	4369
2009-12-31	4525
2010-03-31	4771
2010-06-30	4750
2010-09-30	5188
2010-12-31	4246
2011-03-31	5250
2011-06-30	5492
2011-09-30	5576
2011-12-31	4796
2012-03-31	8096
2012-06-30	4934
2012-09-30	6151
2012-12-31	5801
2013-03-31	6792
2013-06-30	6292
2013-09-30	6366
2013-12-31	5834
2014-03-31	8432
2014-06-30	9388
2014-09-30	10298
2014-12-31	8567
2015-03-31	10701
2015-06-30	8358
2015-09-30	10454
2015-12-31	9036
2016-03-31	7925
2016-06-30	8903
2016-09-30	9295
2016-12-31	8421
2017-03-31	10403
2017-06-30	10307
2017-09-30	12501
2017-12-31	12097
2018-03-31	14649
2018-06-30	11543
2018-09-30	10523
2018-12-31	9284
2019-03-31	10884
2019-06-30	9328
2019-09-30	18253
2019-12-31	17150
2020-03-31	16724
2020-06-30	15717
2020-09-30	17873
2020-12-31	20077
2021-03-31	16590
2021-06-30	21200
2021-09-30	19076
2021-12-31	16737
2022-03-31	17192
2022-06-30	15958
2022-09-30	19501
2022-12-31	19625
2023-03-31	19760
2023-06-30	19568
2023-09-30	20681