Quarter	US dollars
1999-03-31	12644
1999-06-30	14764
1999-09-30	11746
1999-12-31	10598
2000-03-31	11553
2000-06-30	12437
2000-09-30	11409
2000-12-31	10534
2001-03-31	11566
2001-06-30	10938
2001-09-30	10039
2001-12-31	8442
2002-03-31	10242
2002-06-30	8088
2002-09-30	8517
2002-12-31	9808
2003-03-31	12360
2003-06-30	13427
2003-09-30	13996
2003-12-31	16147
2004-03-31	15009
2004-06-30	15894
2004-09-30	18756
2004-12-31	20718
2005-03-31	27975
2005-06-30	26422
2005-09-30	23303
2005-12-31	18613
2006-03-31	20536
2006-06-30	19454
2006-09-30	25790
2006-12-31	24727
2007-03-31	27619
2007-06-30	29634
2007-09-30	28202
2007-12-31	35765
2008-03-31	30809
2008-06-30	38178
2008-09-30	25126
2008-12-31	19889
2009-03-31	30497
2009-06-30	31071
2009-09-30	24107
2009-12-31	20108
2010-03-31	19575
2010-06-30	20184
2010-09-30	31826
2010-12-31	25931
2011-03-31	25881
2011-06-30	25536
2011-09-30	26096
2011-12-31	19316
2012-03-31	27071
2012-06-30	22493
2012-09-30	25731
2012-12-31	19389
2013-03-31	19275
2013-06-30	19904
2013-09-30	23036
2013-12-31	20809
2014-03-31	18596
2014-06-30	16430
2014-09-30	12069
2014-12-31	11599
2015-03-31	14556
2015-06-30	13381
2015-09-30	13035
2015-12-31	9382
2016-03-31	10823
2016-06-30	10991
2016-09-30	12885
2016-12-31	12253
2017-03-31	10193
2017-06-30	11565
2017-09-30	12488
2017-12-31	13950
2018-03-31	13615
2018-06-30	10235
2018-09-30	8074
2018-12-31	6220
2019-03-31	5669
2019-06-30	6631
2019-09-30	6953
2019-12-31	6138
2020-03-31	7200
2020-06-30	5295
2020-09-30	4791
2020-12-31	7181
2021-03-31	5767
2021-06-30	5152
2021-09-30	5509
2021-12-31	8162
2022-03-31	7047
2022-06-30	7041
2022-09-30	4761
2022-12-31	7979
2023-03-31	8358
2023-06-30	7029
2023-09-30	8476