Quarter	US dollars
1999-03-31	12086
1999-06-30	11593
1999-09-30	10547
1999-12-31	9893
2000-03-31	9780
2000-06-30	9274
2000-09-30	9051
2000-12-31	10267
2001-03-31	8766
2001-06-30	8685
2001-09-30	8765
2001-12-31	7839
2002-03-31	7871
2002-06-30	8061
2002-09-30	7118
2002-12-31	7130
2003-03-31	7157
2003-06-30	7323
2003-09-30	9063
2003-12-31	11927
2004-03-31	13356
2004-06-30	14211
2004-09-30	13359
2004-12-31	15269
2005-03-31	21096
2005-06-30	23437
2005-09-30	24667
2005-12-31	30819
2006-03-31	40443
2006-06-30	36678
2006-09-30	39642
2006-12-31	35059
2007-03-31	42073
2007-06-30	43386
2007-09-30	53508
2007-12-31	50432
2008-03-31	50779
2008-06-30	47951
2008-09-30	54467
2008-12-31	40849
2009-03-31	33582
2009-06-30	40571
2009-09-30	33296
2009-12-31	32193
2010-03-31	34974
2010-06-30	37425
2010-09-30	45649
2010-12-31	39822
2011-03-31	51585
2011-06-30	53956
2011-09-30	43684
2011-12-31	46299
2012-03-31	49039
2012-06-30	48201
2012-09-30	52466
2012-12-31	51581
2013-03-31	64455
2013-06-30	63654
2013-09-30	64786
2013-12-31	60252
2014-03-31	58598
2014-06-30	60234
2014-09-30	58919
2014-12-31	52428
2015-03-31	49567
2015-06-30	50772
2015-09-30	47499
2015-12-31	45051
2016-03-31	43414
2016-06-30	45771
2016-09-30	45187
2016-12-31	40206
2017-03-31	44836
2017-06-30	39912
2017-09-30	41897
2017-12-31	44151
2018-03-31	44376
2018-06-30	38903
2018-09-30	34024
2018-12-31	34190
2019-03-31	34692
2019-06-30	28404
2019-09-30	25518
2019-12-31	31001
2020-03-31	24689
2020-06-30	20903
2020-09-30	23549
2020-12-31	23460
2021-03-31	21287
2021-06-30	20581
2021-09-30	20489
2021-12-31	22873
2022-03-31	24983
2022-06-30	26163
2022-09-30	28311
2022-12-31	22055
2023-03-31	21090
2023-06-30	22058
2023-09-30	24224