Quarter	US dollars
1999-03-31	4125
1999-06-30	3534
1999-09-30	4352
1999-12-31	3928
2000-03-31	4282
2000-06-30	3884
2000-09-30	4059
2000-12-31	4009
2001-03-31	4912
2001-06-30	4617
2001-09-30	3840
2001-12-31	4849
2002-03-31	5008
2002-06-30	3783
2002-09-30	4089
2002-12-31	3865
2003-03-31	3654
2003-06-30	3208
2003-09-30	3174
2003-12-31	4225
2004-03-31	4736
2004-06-30	5231
2004-09-30	4444
2004-12-31	5610
2005-03-31	6292
2005-06-30	8349
2005-09-30	6688
2005-12-31	6381
2006-03-31	8408
2006-06-30	10666
2006-09-30	8919
2006-12-31	7443
2007-03-31	10462
2007-06-30	8731
2007-09-30	8449
2007-12-31	10561
2008-03-31	9434
2008-06-30	11371
2008-09-30	7819
2008-12-31	3505
2009-03-31	2093
2009-06-30	2296
2009-09-30	3809
2009-12-31	2763
2010-03-31	3624
2010-06-30	3008
2010-09-30	5430
2010-12-31	3853
2011-03-31	8818
2011-06-30	8649
2011-09-30	7050
2011-12-31	5153
2012-03-31	4818
2012-06-30	5147
2012-09-30	5607
2012-12-31	5251
2013-03-31	5964
2013-06-30	5277
2013-09-30	5700
2013-12-31	8062
2014-03-31	6258
2014-06-30	8127
2014-09-30	7784
2014-12-31	8536
2015-03-31	8950
2015-06-30	10118
2015-09-30	9275
2015-12-31	5863
2016-03-31	4479
2016-06-30	12434
2016-09-30	11795
2016-12-31	10067
2017-03-31	12017
2017-06-30	9938
2017-09-30	6945
2017-12-31	8004
2018-03-31	11898
2018-06-30	5347
2018-09-30	7262
2018-12-31	10045
2019-03-31	7069
2019-06-30	6461
2019-09-30	6668
2019-12-31	5458
2020-03-31	8658
2020-06-30	7344
2020-09-30	6751
2020-12-31	7792
2021-03-31	2102
2021-06-30	3833
2021-09-30	3813
2021-12-31	1916
2022-03-31	3905
2022-06-30	3911
2022-09-30	4807
2022-12-31	4992
2023-03-31	4514
2023-06-30	4304
2023-09-30	7500