Quarter	US dollars
1999-03-31	10881
1999-06-30	10638
1999-09-30	11297
1999-12-31	11207
2000-03-31	11981
2000-06-30	12228
2000-09-30	13634
2000-12-31	13010
2001-03-31	12974
2001-06-30	11692
2001-09-30	12934
2001-12-31	13580
2002-03-31	14537
2002-06-30	14497
2002-09-30	15452
2002-12-31	16831
2003-03-31	15678
2003-06-30	15870
2003-09-30	18296
2003-12-31	18299
2004-03-31	21886
2004-06-30	24170
2004-09-30	23162
2004-12-31	27901
2005-03-31	27014
2005-06-30	26884
2005-09-30	29943
2005-12-31	36152
2006-03-31	40883
2006-06-30	39281
2006-09-30	41954
2006-12-31	47532
2007-03-31	55741
2007-06-30	66874
2007-09-30	73023
2007-12-31	76304
2008-03-31	80186
2008-06-30	83718
2008-09-30	73773
2008-12-31	64097
2009-03-31	60134
2009-06-30	59812
2009-09-30	60366
2009-12-31	58234
2010-03-31	56005
2010-06-30	51838
2010-09-30	56895
2010-12-31	53352
2011-03-31	54804
2011-06-30	55719
2011-09-30	49134
2011-12-31	50994
2012-03-31	48376
2012-06-30	53052
2012-09-30	55251
2012-12-31	59487
2013-03-31	65301
2013-06-30	57609
2013-09-30	57073
2013-12-31	56837
2014-03-31	49653
2014-06-30	52130
2014-09-30	47733
2014-12-31	42863
2015-03-31	36562
2015-06-30	36496
2015-09-30	35389
2015-12-31	33947
2016-03-31	35959
2016-06-30	35147
2016-09-30	34274
2016-12-31	30680
2017-03-31	31562
2017-06-30	31927
2017-09-30	31279
2017-12-31	31713
2018-03-31	32467
2018-06-30	30875
2018-09-30	30145
2018-12-31	29575
2019-03-31	27711
2019-06-30	27986
2019-09-30	28726
2019-12-31	27490
2020-03-31	26797
2020-06-30	26408
2020-09-30	28648
2020-12-31	28024
2021-03-31	24716
2021-06-30	22682
2021-09-30	23009
2021-12-31	22286
2022-03-31	20957
2022-06-30	19275
2022-09-30	19289
2022-12-31	19742
2023-03-31	20733
2023-06-30	21753
2023-09-30	19523