Quarter	US dollars
1999-03-31	3570
1999-06-30	3597
1999-09-30	3593
1999-12-31	3621
2000-03-31	2538
2000-06-30	2613
2000-09-30	2316
2000-12-31	2526
2001-03-31	2479
2001-06-30	2658
2001-09-30	2652
2001-12-31	2647
2002-03-31	2604
2002-06-30	2281
2002-09-30	2299
2002-12-31	2296
2003-03-31	2207
2003-06-30	2675
2003-09-30	2696
2003-12-31	2768
2004-03-31	2731
2004-06-30	2860
2004-09-30	3359
2004-12-31	4008
2005-03-31	3861
2005-06-30	4141
2005-09-30	3787
2005-12-31	3934
2006-03-31	4090
2006-06-30	4411
2006-09-30	4186
2006-12-31	4282
2007-03-31	3978
2007-06-30	4371
2007-09-30	4200
2007-12-31	4240
2008-03-31	4607
2008-06-30	3998
2008-09-30	4053
2008-12-31	3370
2009-03-31	3274
2009-06-30	3621
2009-09-30	2963
2009-12-31	2716
2010-03-31	2715
2010-06-30	2516
2010-09-30	3039
2010-12-31	3635
2011-03-31	3218
2011-06-30	2837
2011-09-30	2555
2011-12-31	3299
2012-03-31	2209
2012-06-30	2335
2012-09-30	2117
2012-12-31	2148
2013-03-31	2203
2013-06-30	2110
2013-09-30	2080
2013-12-31	1567
2014-03-31	1928
2014-06-30	1327
2014-09-30	1325
2014-12-31	1113
2015-03-31	708
2015-06-30	1190
2015-09-30	1066
2015-12-31	1109
2016-03-31	948
2016-06-30	1424
2016-09-30	1464
2016-12-31	1552
2017-03-31	1681
2017-06-30	1153
2017-09-30	761
2017-12-31	1714
2018-03-31	693
2018-06-30	570
2018-09-30	1250
2018-12-31	1059
2019-03-31	526
2019-06-30	627
2019-09-30	1099
2019-12-31	444
2020-03-31	3950
2020-06-30	3817
2020-09-30	683
2020-12-31	399
2021-03-31	1499
2021-06-30	2131
2021-09-30	2466
2021-12-31	2268
2022-03-31	1816
2022-06-30	599
2022-09-30	1211
2022-12-31	1305
2023-03-31	1426
2023-06-30	594
2023-09-30	533