Quarter	Millions of US Dollars
1976-01-01	17
1976-04-01	37
1976-07-01	37
1976-10-01	38
1977-01-01	38
1977-04-01	38
1977-07-01	38
1977-10-01	38
1978-01-01	39
1978-04-01	69
1978-07-01	69
1978-10-01	69
1979-01-01	69
1979-04-01	69
1979-07-01	69
1979-10-01	70
1980-01-01	70
1980-04-01	95
1980-07-01	95
1980-10-01	95
1981-01-01	77
1981-04-01	77
1981-07-01	77
1981-10-01	77
1982-01-01	77
1982-04-01	77
1982-07-01	77
1982-10-01	77
1983-01-01	77
1983-04-01	55
1983-07-01	55
1983-10-01	55
1984-01-01	55
1984-04-01	55
1984-07-01	55
1984-10-01	55
1985-01-01	55
1985-04-01	25
1985-07-01	25
1985-10-01	17
1986-01-01	17
1986-04-01	17
1986-07-01	17
1986-10-01	9
1987-01-01	9
1996-04-01	220
1996-07-01	545
1996-10-01	410
1997-01-01	410
1997-04-01	635
1997-07-01	632
1997-10-01	625
1998-01-01	619
1998-04-01	1167
1998-07-01	1222
1998-10-01	1216
1999-01-01	1580
1999-04-01	1530
1999-07-01	1568
1999-10-01	1495
2000-01-01	1823
2000-04-01	1819
2000-07-01	1700
2000-10-01	1778
2001-01-01	1795
2001-04-01	2116
2001-07-01	1924
2001-10-01	1865
2002-01-01	1847
2002-04-01	2090
2002-07-01	2066
2002-10-01	2222
2003-01-01	2316
2003-04-01	2423
2003-07-01	2471
2003-10-01	2669
2004-01-01	2576
2004-04-01	2309
2004-07-01	2357
2004-10-01	2649
2005-01-01	2522
2005-04-01	1745
2005-07-01	1738
2005-10-01	1699
2006-01-01	1759
2006-04-01	1843
2006-07-01	1836
2006-10-01	1901
2007-01-01	3396
2007-04-01	3444
2007-07-01	3616
2007-10-01	3901
2008-01-01	5771
2008-04-01	5754
2008-07-01	5221
2008-10-01	5080
2009-01-01	4325
2009-04-01	4594
2009-07-01	7688
2009-10-01	8180
2010-01-01	6999
2010-04-01	7564
2010-07-01	8380
2010-10-01	8277
2011-01-01	9279
2011-04-01	8784
2011-07-01	8226
2011-10-01	7895
2012-01-01	8140
2012-04-01	7690
2012-07-01	5304
2012-10-01	7656
2013-01-01	7762
2013-04-01	11374
2013-07-01	11427
2013-10-01	11541
2014-01-01	15040
2014-04-01	18214
2014-07-01	17910
2014-10-01	17555
2015-01-01	16644
2015-04-01	15473
2015-07-01	15817
2015-10-01	15640
2016-01-01	15833
2016-04-01	15732
2016-07-01	15765
2016-10-01	14804
2017-01-01	14883
2017-04-01	15263
2017-07-01	15116
2017-10-01	14010
2018-01-01	12908
2018-04-01	11711