Quarter	US dollars
1999-03-31	22967
1999-06-30	22231
1999-09-30	21844
1999-12-31	21100
2000-03-31	21761
2000-06-30	21502
2000-09-30	22685
2000-12-31	23247
2001-03-31	21740
2001-06-30	20377
2001-09-30	21698
2001-12-31	21419
2002-03-31	22408
2002-06-30	22558
2002-09-30	22570
2002-12-31	23961
2003-03-31	22835
2003-06-30	23193
2003-09-30	27358
2003-12-31	30226
2004-03-31	35242
2004-06-30	38381
2004-09-30	36520
2004-12-31	43170
2005-03-31	48110
2005-06-30	50321
2005-09-30	54609
2005-12-31	66971
2006-03-31	81326
2006-06-30	75959
2006-09-30	81597
2006-12-31	82591
2007-03-31	97814
2007-06-30	110260
2007-09-30	126531
2007-12-31	126736
2008-03-31	130965
2008-06-30	131669
2008-09-30	128240
2008-12-31	104945
2009-03-31	93715
2009-06-30	100383
2009-09-30	93663
2009-12-31	90427
2010-03-31	90979
2010-06-30	89263
2010-09-30	102544
2010-12-31	93174
2011-03-31	106388
2011-06-30	109675
2011-09-30	92818
2011-12-31	97292
2012-03-31	97415
2012-06-30	101253
2012-09-30	107716
2012-12-31	111068
2013-03-31	129756
2013-06-30	121262
2013-09-30	121859
2013-12-31	117090
2014-03-31	108251
2014-06-30	112364
2014-09-30	106651
2014-12-31	95290
2015-03-31	86129
2015-06-30	87268
2015-09-30	82888
2015-12-31	78998
2016-03-31	79372
2016-06-30	80918
2016-09-30	79461
2016-12-31	70886
2017-03-31	76399
2017-06-30	71839
2017-09-30	73176
2017-12-31	75864
2018-03-31	76843
2018-06-30	69778
2018-09-30	64169
2018-12-31	63765
2019-03-31	62403
2019-06-30	56390
2019-09-30	54244
2019-12-31	58491
2020-03-31	51486
2020-06-30	47311
2020-09-30	52197
2020-12-31	51484
2021-03-31	46003
2021-06-30	43263
2021-09-30	43498
2021-12-31	45159
2022-03-31	45940
2022-06-30	45438
2022-09-30	47600
2022-12-31	41798
2023-03-31	41823
2023-06-30	43811
2023-09-30	43746