Quarter	US dollars
1999-03-31	12746
1999-06-30	13410
1999-09-30	14913
1999-12-31	12977
2000-03-31	12292
2000-06-30	10724
2000-09-30	10970
2000-12-31	11779
2001-03-31	12375
2001-06-30	11202
2001-09-30	11996
2001-12-31	15246
2002-03-31	15521
2002-06-30	18571
2002-09-30	16042
2002-12-31	16982
2003-03-31	19827
2003-06-30	22421
2003-09-30	28329
2003-12-31	29013
2004-03-31	36721
2004-06-30	34483
2004-09-30	34667
2004-12-31	31537
2005-03-31	36729
2005-06-30	45296
2005-09-30	44539
2005-12-31	35351
2006-03-31	44497
2006-06-30	41858
2006-09-30	43638
2006-12-31	38048
2007-03-31	47760
2007-06-30	56351
2007-09-30	49980
2007-12-31	39452
2008-03-31	63369
2008-06-30	64108
2008-09-30	49082
2008-12-31	39496
2009-03-31	42610
2009-06-30	37264
2009-09-30	33089
2009-12-31	28487
2010-03-31	36729
2010-06-30	32143
2010-09-30	35414
2010-12-31	26307
2011-03-31	40567
2011-06-30	44408
2011-09-30	47738
2011-12-31	39665
2012-03-31	44553
2012-06-30	47070
2012-09-30	44595
2012-12-31	53884
2013-03-31	47057
2013-06-30	51565
2013-09-30	46171
2013-12-31	44479
2014-03-31	38516
2014-06-30	40060
2014-09-30	36617
2014-12-31	30340
2015-03-31	36428
2015-06-30	43513
2015-09-30	40149
2015-12-31	33070
2016-03-31	29669
2016-06-30	33506
2016-09-30	34541
2016-12-31	31530
2017-03-31	31946
2017-06-30	33427
2017-09-30	33546
2017-12-31	32306
2018-03-31	34897
2018-06-30	39247
2018-09-30	40185
2018-12-31	40528
2019-03-31	38294
2019-06-30	43170
2019-09-30	43280
2019-12-31	47930
2020-03-31	50455
2020-06-30	47893
2020-09-30	48443
2020-12-31	46811
2021-03-31	43562
2021-06-30	50987
2021-09-30	62665
2021-12-31	61102
2022-03-31	62858
2022-06-30	58097
2022-09-30	45452
2022-12-31	43924
2023-03-31	28986
2023-06-30	30211
2023-09-30	28272