Quarter	US dollars
1999-03-31	4642
1999-06-30	4909
1999-09-30	4892
1999-12-31	5150
2000-03-31	5405
2000-06-30	5363
2000-09-30	5532
2000-12-31	6054
2001-03-31	6234
2001-06-30	5779
2001-09-30	6085
2001-12-31	6252
2002-03-31	5827
2002-06-30	7213
2002-09-30	7533
2002-12-31	8640
2003-03-31	8353
2003-06-30	10827
2003-09-30	10413
2003-12-31	11489
2004-03-31	13042
2004-06-30	14349
2004-09-30	15119
2004-12-31	17424
2005-03-31	18909
2005-06-30	17204
2005-09-30	18675
2005-12-31	18056
2006-03-31	22427
2006-06-30	22042
2006-09-30	25256
2006-12-31	25172
2007-03-31	28097
2007-06-30	28600
2007-09-30	28146
2007-12-31	26248
2008-03-31	28774
2008-06-30	28513
2008-09-30	33815
2008-12-31	27119
2009-03-31	22340
2009-06-30	22529
2009-09-30	36271
2009-12-31	24121
2010-03-31	23200
2010-06-30	20726
2010-09-30	21779
2010-12-31	21966
2011-03-31	24075
2011-06-30	23298
2011-09-30	24262
2011-12-31	22424
2012-03-31	25129
2012-06-30	24910
2012-09-30	24398
2012-12-31	22407
2013-03-31	22503
2013-06-30	22613
2013-09-30	24928
2013-12-31	25295
2014-03-31	23671
2014-06-30	25361
2014-09-30	23416
2014-12-31	21829
2015-03-31	21402
2015-06-30	22504
2015-09-30	23935
2015-12-31	24127
2016-03-31	24281
2016-06-30	24950
2016-09-30	22974
2016-12-31	20384
2017-03-31	20188
2017-06-30	21031
2017-09-30	21583
2017-12-31	24018
2018-03-31	25077
2018-06-30	23804
2018-09-30	23494
2018-12-31	23373
2019-03-31	22483
2019-06-30	22217
2019-09-30	23073
2019-12-31	23730
2020-03-31	23666
2020-06-30	20986
2020-09-30	21483
2020-12-31	22943
2021-03-31	22026
2021-06-30	24142
2021-09-30	23772
2021-12-31	22166
2022-03-31	19569
2022-06-30	16692
2022-09-30	15537
2022-12-31	16917
2023-03-31	15418
2023-06-30	15438
2023-09-30	14454