Quarter	US dollars
1999-03-31	55841
1999-06-30	56333
1999-09-30	53898
1999-12-31	49792
2000-03-31	53425
2000-06-30	58058
2000-09-30	52372
2000-12-31	53043
2001-03-31	58486
2001-06-30	59727
2001-09-30	57241
2001-12-31	52476
2002-03-31	49304
2002-06-30	49671
2002-09-30	43832
2002-12-31	41121
2003-03-31	39299
2003-06-30	43726
2003-09-30	39550
2003-12-31	40428
2004-03-31	38897
2004-06-30	40280
2004-09-30	35952
2004-12-31	42188
2005-03-31	40466
2005-06-30	35633
2005-09-30	36633
2005-12-31	60461
2006-03-31	59810
2006-06-30	64906
2006-09-30	69025
2006-12-31	72384
2007-03-31	78566
2007-06-30	77470
2007-09-30	75608
2007-12-31	77130
2008-03-31	92287
2008-06-30	95695
2008-09-30	89864
2008-12-31	88445
2009-03-31	78604
2009-06-30	78770
2009-09-30	66710
2009-12-31	72805
2010-03-31	75799
2010-06-30	70957
2010-09-30	72283
2010-12-31	75208
2011-03-31	73320
2011-06-30	69433
2011-09-30	56091
2011-12-31	48332
2012-03-31	57580
2012-06-30	45539
2012-09-30	44619
2012-12-31	49877
2013-03-31	45865
2013-06-30	40543
2013-09-30	42836
2013-12-31	38904
2014-03-31	39212
2014-06-30	38645
2014-09-30	33555
2014-12-31	29964
2015-03-31	25535
2015-06-30	25667
2015-09-30	24115
2015-12-31	24927
2016-03-31	25378
2016-06-30	25682
2016-09-30	23949
2016-12-31	24871
2017-03-31	29483
2017-06-30	29302
2017-09-30	30960
2017-12-31	32108
2018-03-31	29649
2018-06-30	28239
2018-09-30	23038
2018-12-31	20962
2019-03-31	22082
2019-06-30	24047
2019-09-30	24259
2019-12-31	26801
2020-03-31	26311
2020-06-30	25576
2020-09-30	23091
2020-12-31	20248
2021-03-31	18623
2021-06-30	16846
2021-09-30	14087
2021-12-31	13369
2022-03-31	12765
2022-06-30	10386
2022-09-30	7363
2022-12-31	4342
2023-03-31	4535
2023-06-30	4520
2023-09-30	4345