Quarter	US dollars
1999-03-31	6693
1999-06-30	6562
1999-09-30	7121
1999-12-31	7007
2000-03-31	6627
2000-06-30	5762
2000-09-30	6387
2000-12-31	6167
2001-03-31	6363
2001-06-30	5952
2001-09-30	5456
2001-12-31	6025
2002-03-31	5839
2002-06-30	5687
2002-09-30	5647
2002-12-31	5490
2003-03-31	5173
2003-06-30	4919
2003-09-30	4927
2003-12-31	4557
2004-03-31	8345
2004-06-30	5220
2004-09-30	4096
2004-12-31	4993
2005-03-31	4564
2005-06-30	4175
2005-09-30	4169
2005-12-31	4278
2006-03-31	5401
2006-06-30	6122
2006-09-30	6300
2006-12-31	7317
2007-03-31	7051
2007-06-30	6728
2007-09-30	7305
2007-12-31	5998
2008-03-31	5801
2008-06-30	5996
2008-09-30	5835
2008-12-31	5115
2009-03-31	4532
2009-06-30	4020
2009-09-30	5211
2009-12-31	4632
2010-03-31	6078
2010-06-30	5213
2010-09-30	5769
2010-12-31	5783
2011-03-31	5654
2011-06-30	7025
2011-09-30	6895
2011-12-31	8121
2012-03-31	10948
2012-06-30	8218
2012-09-30	9307
2012-12-31	11073
2013-03-31	10761
2013-06-30	7997
2013-09-30	8856
2013-12-31	9119
2014-03-31	7194
2014-06-30	6817
2014-09-30	6494
2014-12-31	5650
2015-03-31	5744
2015-06-30	4590
2015-09-30	4395
2015-12-31	2986
2016-03-31	2640
2016-06-30	2254
2016-09-30	2555
2016-12-31	2636
2017-03-31	2650
2017-06-30	3230
2017-09-30	3755
2017-12-31	2683
2018-03-31	3344
2018-06-30	2210
2018-09-30	2593
2018-12-31	2930
2019-03-31	3062
2019-06-30	3438
2019-09-30	3015
2019-12-31	2988
2020-03-31	2798
2020-06-30	2607
2020-09-30	2180
2020-12-31	7139
2021-03-31	5118
2021-06-30	5067
2021-09-30	5033
2021-12-31	4810
2022-03-31	5150
2022-06-30	4645
2022-09-30	4515
2022-12-31	4535
2023-03-31	5366
2023-06-30	5783
2023-09-30	4083