Quarter	Millions of US Dollars
1977-04-01	10
1977-07-01	10
1977-10-01	10
1978-01-01	10
1978-04-01	10
1978-07-01	11
1978-10-01	11
1979-01-01	10
1979-04-01	10
1979-07-01	10
1979-10-01	10
1980-01-01	11
1980-04-01	11
1980-07-01	11
1980-10-01	11
1981-01-01	10
1981-04-01	10
1981-07-01	10
1981-10-01	10
1982-01-01	10
1984-10-01	200
1985-01-01	200
1985-04-01	200
1985-07-01	200
1985-10-01	200
1986-01-01	200
1986-04-01	200
1986-07-01	200
1986-10-01	200
1987-01-01	200
1987-04-01	200
1987-07-01	200
2004-10-01	187
2005-01-01	787
2005-04-01	787
2005-07-01	787
2005-10-01	1487
2006-01-01	1487
2006-04-01	2900
2006-07-01	3324
2006-10-01	3885
2007-01-01	3872
2007-04-01	3890
2007-07-01	3927
2007-10-01	3950
2008-01-01	3921
2008-04-01	5261
2008-07-01	5144
2008-10-01	5088
2009-01-01	5147
2009-04-01	5266
2009-07-01	7166
2009-10-01	7361
2010-01-01	7579
2010-04-01	7519
2010-07-01	7610
2010-10-01	7530
2011-01-01	7544
2011-04-01	6080
2011-07-01	5994
2011-10-01	6992
2012-01-01	7019
2012-04-01	8735
2012-07-01	8732
2012-10-01	8722
2013-01-01	7355
2013-04-01	9324
2013-07-01	9321
2013-10-01	9204
2014-01-01	9203
2014-04-01	9836
2014-07-01	9812
2014-10-01	9805
2015-01-01	8946
2015-04-01	8946
2015-07-01	8909
2015-10-01	7777
2016-01-01	7793
2016-04-01	8591
2016-07-01	9438
2016-10-01	40005
2017-01-01	40508
2017-04-01	50070
2017-07-01	50263
2017-10-01	64244
2018-01-01	65213
2018-04-01	76708