Quarter	Millions of US Dollars
1991-04-01	81
1991-07-01	88
1991-10-01	94
1992-01-01	87
1992-04-01	95
1992-07-01	89
1992-10-01	76
1993-01-01	75
1993-04-01	75
1993-07-01	75
1993-10-01	74
1994-01-01	74
1994-04-01	77
1994-07-01	79
1994-10-01	88
1995-01-01	111
1995-04-01	110
1995-07-01	114
1995-10-01	103
1996-01-01	101
1996-04-01	102
1996-07-01	103
1996-10-01	110
1997-01-01	86
1997-04-01	88
1997-07-01	81
1997-10-01	83
1998-01-01	84
1998-04-01	83
1998-07-01	85
1998-10-01	83
1999-01-01	88
1999-04-01	138
1999-07-01	119
1999-10-01	169
2000-01-01	163
2000-04-01	250
2000-07-01	243
2000-10-01	800
2001-01-01	1098
2001-04-01	2379
2001-07-01	3581
2001-10-01	3836
2002-01-01	4011
2002-04-01	5103
2002-07-01	3666
2002-10-01	4230
2003-01-01	4212
2003-04-01	4473
2003-07-01	4799
2003-10-01	5133
2004-01-01	5225
2004-04-01	5171
2004-07-01	4526
2004-10-01	4318
2005-01-01	4281
2005-04-01	4093
2005-07-01	4262
2005-10-01	4201
2006-01-01	4297
2006-04-01	4387
2006-07-01	3470
2006-10-01	3468
2007-01-01	3252
2007-04-01	3487
2007-07-01	4285
2007-10-01	3957
2008-01-01	4085
2008-04-01	3866
2008-07-01	3271
2008-10-01	3053
2009-01-01	2866
2009-04-01	2930
2009-07-01	2906
2009-10-01	2779
2010-01-01	2453
2010-04-01	2328
2010-07-01	2398
2010-10-01	2207
2011-01-01	2071
2011-04-01	1906
2011-07-01	1782
2011-10-01	1731
2012-01-01	1602
2012-04-01	1464
2012-07-01	1494
2012-10-01	1481
2013-01-01	1436
2013-04-01	985
2013-07-01	1016
2013-10-01	1028
2014-01-01	1031
2014-04-01	1036
2014-07-01	988
2014-10-01	912
2015-01-01	769
2015-04-01	794
2015-07-01	479
2015-10-01	473
2016-01-01	470
2016-04-01	463
2016-07-01	464
2016-10-01	452
2017-01-01	418
2017-04-01	432
2017-07-01	309
2017-10-01	236
2018-01-01	239
2018-04-01	164