Quarter	Millions of US Dollars
1997-10-01	11772
1998-01-01	12237
1998-04-01	12088
1998-07-01	12786
1998-10-01	13818
1999-01-01	11564
1999-04-01	10762
1999-07-01	10597
1999-10-01	10107
2000-01-01	9373
2000-04-01	9364
2000-07-01	9518
2000-10-01	9515
2001-01-01	9604
2001-04-01	9443
2001-07-01	9468
2001-10-01	8562
2002-01-01	6974
2002-04-01	7033
2002-07-01	6892
2002-10-01	7873
2003-01-01	7950
2003-04-01	8260
2003-07-01	8814
2003-10-01	9951
2004-01-01	9100
2004-04-01	9473
2004-07-01	9917
2004-10-01	11847
2005-01-01	11284
2005-04-01	10816
2005-07-01	10772
2005-10-01	10789
2006-01-01	11143
2006-04-01	10749
2006-07-01	12591
2006-10-01	14932
2007-01-01	23240
2007-04-01	21672
2007-07-01	24500
2007-10-01	22535
2008-01-01	25744
2008-04-01	29454
2008-07-01	26812
2008-10-01	26382
2009-01-01	23897
2009-04-01	33231
2009-07-01	38566
2009-10-01	38451
2010-01-01	41429
2010-04-01	33065
2010-07-01	38943
2010-10-01	32880
2011-01-01	41924
2011-04-01	44198
2011-07-01	35920
2011-10-01	28229
2012-01-01	31825
2012-04-01	30599
2012-07-01	31656
2012-10-01	31483
2013-01-01	33177
2013-04-01	33910
2013-07-01	34027
2013-10-01	38875
2014-01-01	37254
2014-04-01	34736
2014-07-01	12647
2014-10-01	12410
2015-01-01	11311
2015-04-01	12140
2015-07-01	12039
2015-10-01	12060
2016-01-01	11836
2016-04-01	10474
2016-07-01	9421
2016-10-01	8743
2017-01-01	9765
2017-04-01	9551
2017-07-01	9345
2017-10-01	9284
2018-01-01	9187