Quarter	US dollars
1999-03-31	8638
1999-06-30	8223
1999-09-30	8424
1999-12-31	7009
2000-03-31	7844
2000-06-30	7954
2000-09-30	7449
2000-12-31	8491
2001-03-31	7190
2001-06-30	7598
2001-09-30	6793
2001-12-31	6291
2002-03-31	6355
2002-06-30	7378
2002-09-30	7103
2002-12-31	8098
2003-03-31	9200
2003-06-30	9690
2003-09-30	10888
2003-12-31	11889
2004-03-31	9535
2004-06-30	9604
2004-09-30	9520
2004-12-31	10836
2005-03-31	10183
2005-06-30	10107
2005-09-30	9477
2005-12-31	9627
2006-03-31	9973
2006-06-30	10445
2006-09-30	11335
2006-12-31	13530
2007-03-31	13777
2007-06-30	19771
2007-09-30	18627
2007-12-31	19942
2008-03-31	23212
2008-06-30	21299
2008-09-30	18430
2008-12-31	18525
2009-03-31	14993
2009-06-30	14715
2009-09-30	14741
2009-12-31	14752
2010-03-31	14545
2010-06-30	16257
2010-09-30	17596
2010-12-31	17440
2011-03-31	15488
2011-06-30	18355
2011-09-30	17707
2011-12-31	16199
2012-03-31	18422
2012-06-30	19582
2012-09-30	19389
2012-12-31	19558
2013-03-31	19574
2013-06-30	18238
2013-09-30	22216
2013-12-31	20568
2014-03-31	19467
2014-06-30	19731
2014-09-30	17887
2014-12-31	14627
2015-03-31	19465
2015-06-30	19522
2015-09-30	19925
2015-12-31	17068