Quarter	Millions of US Dollars
1977-01-01	0
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	0
1980-01-01	0
1980-04-01	0
1980-07-01	0
1980-10-01	0
1981-01-01	48
1981-04-01	42
1981-07-01	43
1981-10-01	44
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	78
1995-01-01	73
1995-04-01	71
1995-07-01	76
1995-10-01	0
1996-01-01	0
1996-04-01	0
1996-07-01	0
1996-10-01	0
1997-01-01	0
1997-04-01	0
1997-07-01	0
1997-10-01	138
1998-01-01	138
1998-04-01	388
1998-07-01	392
1998-10-01	248
1999-01-01	261
1999-04-01	20
1999-07-01	170
1999-10-01	170
2000-01-01	150
2000-04-01	150
2000-07-01	0
2000-10-01	0
2001-01-01	0
2001-04-01	75
2001-07-01	0
2001-10-01	0
2002-01-01	0
2002-04-01	0
2002-07-01	0
2002-10-01	0
2003-01-01	0
2003-04-01	18
2003-07-01	18
2003-10-01	18
2004-01-01	18
2004-04-01	0
2004-07-01	503
2004-10-01	605
2005-01-01	503
2005-04-01	900
2005-07-01	504
2005-10-01	1052
2006-01-01	1925
2006-04-01	2078
2006-07-01	3900
2006-10-01	5222
2007-01-01	10613
2007-04-01	10498
2007-07-01	9895
2007-10-01	9006
2008-01-01	7624
2008-04-01	7568
2008-07-01	7793
2008-10-01	9582
2009-01-01	9125
2009-04-01	11505
2009-07-01	12739
2009-10-01	9295
2010-01-01	8870
2010-04-01	9377
2010-07-01	11195
2010-10-01	10600
2011-01-01	13054
2011-04-01	13548
2011-07-01	11975
2011-10-01	14407
2012-01-01	13053
2012-04-01	13526
2012-07-01	15048
2012-10-01	12965
2013-01-01	13967
2013-04-01	17239
2013-07-01	21675
2013-10-01	25610
2014-01-01	25466
2014-04-01	20461
2014-07-01	15791
2014-10-01	13478
2015-01-01	12463
2015-04-01	18031
2015-07-01	21487
2015-10-01	22528
2016-01-01	30104
2016-04-01	27054
2016-07-01	28861
2016-10-01	27998
2017-01-01	25214
2017-04-01	24952
2017-07-01	21430
2017-10-01	19843
2018-01-01	16690
2018-04-01	21174