Quarter	US dollars
1999-03-31	3421
1999-06-30	4130
1999-09-30	5584
1999-12-31	5146
2000-03-31	7216
2000-06-30	6347
2000-09-30	8086
2000-12-31	6663
2001-03-31	7936
2001-06-30	8443
2001-09-30	9851
2001-12-31	9113
2002-03-31	8773
2002-06-30	8923
2002-09-30	10689
2002-12-31	9817
2003-03-31	8333
2003-06-30	8999
2003-09-30	8862
2003-12-31	9326
2004-03-31	10068
2004-06-30	11246
2004-09-30	12609
2004-12-31	13357
2005-03-31	15734
2005-06-30	16809
2005-09-30	18936
2005-12-31	18588
2006-03-31	18553
2006-06-30	19907
2006-09-30	20724
2006-12-31	24989
2007-03-31	25970
2007-06-30	33053
2007-09-30	32631
2007-12-31	35355
2008-03-31	32934
2008-06-30	31314
2008-09-30	27422
2008-12-31	22804
2009-03-31	22359
2009-06-30	24434
2009-09-30	26951
2009-12-31	27336
2010-03-31	35782
2010-06-30	32297
2010-09-30	37101
2010-12-31	36822
2011-03-31	39891
2011-06-30	39591
2011-09-30	32496
2011-12-31	29184
2012-03-31	26853
2012-06-30	22334
2012-09-30	20024
2012-12-31	18784
2013-03-31	19512
2013-06-30	20732
2013-09-30	23413
2013-12-31	23343
2014-03-31	19971
2014-06-30	21672
2014-09-30	20298
2014-12-31	19372
2015-03-31	18555
2015-06-30	19318
2015-09-30	17816
2015-12-31	17386
2016-03-31	19183
2016-06-30	19206
2016-09-30	18947
2016-12-31	17495
2017-03-31	19869
2017-06-30	16869
2017-09-30	16840
2017-12-31	17548
2018-03-31	20764
2018-06-30	23100
2018-09-30	19474
2018-12-31	18890
2019-03-31	19710
2019-06-30	20537
2019-09-30	19281
2019-12-31	22105
2020-03-31	22109
2020-06-30	23445
2020-09-30	22807
2020-12-31	36057
2021-03-31	37599
2021-06-30	35136
2021-09-30	31794
2021-12-31	35982
2022-03-31	41107
2022-06-30	32074
2022-09-30	27917
2022-12-31	30894
2023-03-31	29233
2023-06-30	30788
2023-09-30	24407