Quarter	Millions of US Dollars
1987-04-01	0
1987-07-01	0
1987-10-01	0
1988-01-01	0
1988-04-01	0
1988-07-01	0
1988-10-01	0
1989-01-01	0
1989-04-01	0
1989-07-01	0
1989-10-01	0
1990-01-01	0
1990-04-01	0
1990-07-01	0
1990-10-01	0
1991-01-01	0
1991-04-01	0
1991-07-01	0
1991-10-01	0
1992-01-01	0
1992-04-01	0
1992-07-01	0
1992-10-01	0
1993-01-01	0
1993-04-01	0
1993-07-01	0
1993-10-01	0
1994-01-01	0
1994-04-01	0
1994-07-01	0
1994-10-01	0
1995-01-01	0
1995-04-01	0
1995-07-01	0
1995-10-01	0
1996-01-01	0
1996-04-01	0
1996-07-01	0
1996-10-01	1262
1997-01-01	2593
1997-04-01	2332
1997-07-01	2307
1997-10-01	2100
1998-01-01	2347
1998-04-01	2229
1998-07-01	2579
1998-10-01	2864
1999-01-01	3077
1999-04-01	2928
1999-07-01	3460
1999-10-01	3118
2000-01-01	2941
2000-04-01	2724
2000-07-01	2302
2000-10-01	2769
2001-01-01	2992
2001-04-01	3074
2001-07-01	4254
2001-10-01	5780
2002-01-01	6750
2002-04-01	8269
2002-07-01	9821
2002-10-01	10856
2003-01-01	11383
2003-04-01	12262
2003-07-01	13716
2003-10-01	15922
2004-01-01	18229
2004-04-01	18753
2004-07-01	19113
2004-10-01	22288
2005-01-01	23195
2005-04-01	24625
2005-07-01	23627
2005-10-01	24701
2006-01-01	25343
2006-04-01	26962
2006-07-01	26051
2006-10-01	28417
2007-01-01	28461
2007-04-01	28324
2007-07-01	28150
2007-10-01	28281
2008-01-01	30719
2008-04-01	32651
2008-07-01	30097
2008-10-01	27287
2009-01-01	24160
2009-04-01	25021
2009-07-01	25178
2009-10-01	25408
2010-01-01	24041
2010-04-01	23848
2010-07-01	24893
2010-10-01	27986
2011-01-01	28269
2011-04-01	30125
2011-07-01	29264
2011-10-01	29724
2012-01-01	30561
2012-04-01	31658
2012-07-01	33267
2012-10-01	35187
2013-01-01	34788
2013-04-01	33950
2013-07-01	34251
2013-10-01	34535
2014-01-01	34348
2014-04-01	37649
2014-07-01	37250
2014-10-01	40225
2015-01-01	41660
2015-04-01	41643
2015-07-01	39965
2015-10-01	39115
2016-01-01	39756
2016-04-01	39219
2016-07-01	40475
2016-10-01	37305
2017-01-01	41128
2017-04-01	41649
2017-07-01	41183
2017-10-01	41389
2018-01-01	44277