Quarter	US dollars
1999-03-31	2422
1999-06-30	2505
1999-09-30	2461
1999-12-31	2459
2000-03-31	2900
2000-06-30	2588
2000-09-30	3591
2000-12-31	3111
2001-03-31	3093
2001-06-30	3215
2001-09-30	2770
2001-12-31	3172
2002-03-31	3571
2002-06-30	3922
2002-09-30	4456
2002-12-31	5701
2003-03-31	4886
2003-06-30	5237
2003-09-30	6670
2003-12-31	6726
2004-03-31	8916
2004-06-30	10223
2004-09-30	9031
2004-12-31	11507
2005-03-31	10083
2005-06-30	9670
2005-09-30	12823
2005-12-31	17889
2006-03-31	19117
2006-06-30	18534
2006-09-30	17694
2006-12-31	17911
2007-03-31	23984
2007-06-30	33196
2007-09-30	35902
2007-12-31	36502
2008-03-31	40889
2008-06-30	41348
2008-09-30	34817
2008-12-31	27954
2009-03-31	26547
2009-06-30	23508
2009-09-30	21270
2009-12-31	20563
2010-03-31	19450
2010-06-30	17029
2010-09-30	17630
2010-12-31	15236
2011-03-31	14844
2011-06-30	15368
2011-09-30	14772
2011-12-31	19397
2012-03-31	14597
2012-06-30	18012
2012-09-30	18038
2012-12-31	21046
2013-03-31	29427
2013-06-30	25421
2013-09-30	28163
2013-12-31	27692
2014-03-31	24496
2014-06-30	25875
2014-09-30	23698
2014-12-31	17964
2015-03-31	14334
2015-06-30	14196
2015-09-30	12124
2015-12-31	11186
2016-03-31	10601
2016-06-30	10005
2016-09-30	8823
2016-12-31	7493
2017-03-31	7818
2017-06-30	6783
2017-09-30	7608
2017-12-31	7004
2018-03-31	7295
2018-06-30	6101
2018-09-30	6684
2018-12-31	6713
2019-03-31	6423
2019-06-30	7016
2019-09-30	6765
2019-12-31	6219
2020-03-31	7266
2020-06-30	8370
2020-09-30	9070
2020-12-31	8818
2021-03-31	7780
2021-06-30	7385
2021-09-30	7391
2021-12-31	6876
2022-03-31	6898
2022-06-30	5969
2022-09-30	5710
2022-12-31	5712
2023-03-31	5495
2023-06-30	5010
2023-09-30	3839