Quarter	US dollars
1999-03-31	7566
1999-06-30	6391
1999-09-30	6983
1999-12-31	6589
2000-03-31	6497
2000-06-30	5854
2000-09-30	5351
2000-12-31	5609
2001-03-31	5427
2001-06-30	6711
2001-09-30	7094
2001-12-31	7752
2002-03-31	8643
2002-06-30	8663
2002-09-30	9576
2002-12-31	9008
2003-03-31	10632
2003-06-30	8889
2003-09-30	10606
2003-12-31	11833
2004-03-31	11985
2004-06-30	10966
2004-09-30	11899
2004-12-31	12992
2005-03-31	13144
2005-06-30	13177
2005-09-30	14506
2005-12-31	15100
2006-03-31	15393
2006-06-30	16678
2006-09-30	15265
2006-12-31	17365
2007-03-31	18292
2007-06-30	22667
2007-09-30	24884
2007-12-31	25340
2008-03-31	29883
2008-06-30	26788
2008-09-30	25665
2008-12-31	24838
2009-03-31	20682
2009-06-30	20013
2009-09-30	23020
2009-12-31	23389
2010-03-31	23981
2010-06-30	21880
2010-09-30	22685
2010-12-31	21212
2011-03-31	23842
2011-06-30	23180
2011-09-30	23009
2011-12-31	21262
2012-03-31	20838
2012-06-30	20266
2012-09-30	20346
2012-12-31	19047
2013-03-31	19623
2013-06-30	18226
2013-09-30	19460
2013-12-31	18642
2014-03-31	17869
2014-06-30	18858
2014-09-30	20270
2014-12-31	16708
2015-03-31	16058
2015-06-30	16442
2015-09-30	15186
2015-12-31	15282