Quarter	Millions of US Dollars
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
1977-01-01	0
1977-04-01	0
1977-07-01	34
1977-10-01	40
1978-01-01	43
1978-04-01	43
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	0
1981-04-01	12
1981-07-01	30
1981-10-01	54
1982-01-01	51
1982-04-01	62
1982-07-01	45
1982-10-01	37
1983-01-01	37
1983-04-01	12
1983-07-01	39
1983-10-01	28
1984-01-01	43
1984-04-01	69
1984-07-01	41
1984-10-01	114
1985-01-01	174
1985-04-01	149
1985-07-01	150
1985-10-01	105
1986-01-01	30
1986-04-01	31
1986-07-01	32
1986-10-01	2
1987-01-01	2
1987-04-01	75
1987-07-01	99
1987-10-01	100
1988-01-01	100
1988-04-01	24
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	60
1990-04-01	147
1990-07-01	202
1990-10-01	289
1991-01-01	328
1991-04-01	383
1991-07-01	459
1991-10-01	457
1992-01-01	337
1992-04-01	230
1992-07-01	108
1992-10-01	82
1993-01-01	85
1993-04-01	50
1993-07-01	461
1993-10-01	511
1994-01-01	1017
1994-04-01	1421
1994-07-01	1305
1994-10-01	1178
1995-01-01	1002
1995-04-01	743
1995-07-01	993
1995-10-01	669
1996-01-01	915
1996-04-01	971
1996-07-01	758
1996-10-01	776
1997-01-01	611
1997-04-01	530
1997-07-01	444
1997-10-01	348
1998-01-01	517
1998-04-01	585
1998-07-01	627
1998-10-01	618
1999-01-01	1157
1999-04-01	1225
1999-07-01	1123
1999-10-01	1539
2000-01-01	1721
2000-04-01	2735
2000-07-01	2677
2000-10-01	2515
2001-01-01	1934
2001-04-01	1290
2001-07-01	2344
2001-10-01	2051
2002-01-01	1771
2002-04-01	2633
2002-07-01	1482
2002-10-01	1645
2003-01-01	1310
2003-04-01	827
2003-07-01	1362
2003-10-01	2226
2004-01-01	2171
2004-04-01	2556
2004-07-01	2752
2004-10-01	2804
2005-01-01	2687
2005-04-01	2930
2005-07-01	2354
2005-10-01	1354
2006-01-01	1503
2006-04-01	1031
2006-07-01	764
2006-10-01	802
2007-01-01	1349
2007-04-01	1345
2007-07-01	1483
2007-10-01	2189
2008-01-01	2199
2008-04-01	2339
2008-07-01	3315
2008-10-01	3860
2009-01-01	2875
2009-04-01	2791
2009-07-01	3243
2009-10-01	4214
2010-01-01	5360
2010-04-01	6663
2010-07-01	5745
2010-10-01	7646
2011-01-01	7900
2011-04-01	11385
2011-07-01	10773
2011-10-01	8960
2012-01-01	4993
2012-04-01	4939
2012-07-01	5943
2012-10-01	7793
2013-01-01	7277
2013-04-01	7831
2013-07-01	8076
2013-10-01	7027
2014-01-01	8495
2014-04-01	7690
2014-07-01	6774
2014-10-01	7045
2015-01-01	6242
2015-04-01	11987
2015-07-01	13780
2015-10-01	12883
2016-01-01	19139
2016-04-01	14872
2016-07-01	14666
2016-10-01	15507
2017-01-01	15299
2017-04-01	16001
2017-07-01	14869
2017-10-01	16625
2018-01-01	14736
2018-04-01	16182