Quarter	Millions of US Dollars
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	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	45
1979-07-01	48
1979-10-01	47
1980-01-01	41
1980-04-01	0
1980-07-01	0
1980-10-01	0
1981-01-01	0
1981-04-01	0
1981-07-01	0
1981-10-01	0
1982-01-01	8
1982-04-01	7
1982-07-01	16
1982-10-01	17
1983-01-01	10
1983-04-01	10
1983-07-01	0
1983-10-01	0
1984-01-01	0
1984-04-01	0
1984-07-01	0
1984-10-01	87
1985-01-01	87
1985-04-01	87
1985-07-01	87
1985-10-01	46
1986-01-01	50
1986-04-01	50
1986-07-01	63
1986-10-01	17
1987-01-01	14
1987-04-01	14
1987-07-01	1
1987-10-01	1
1988-01-01	8
1988-04-01	8
1988-07-01	48
1988-10-01	163
1989-01-01	305
1989-04-01	455
1989-07-01	446
1989-10-01	334
1990-01-01	310
1990-04-01	162
1990-07-01	132
1990-10-01	329
1991-01-01	314
1991-04-01	619
1991-07-01	688
1991-10-01	521
1992-01-01	367
1992-04-01	77
1992-07-01	66
1992-10-01	59
1993-01-01	58
1993-04-01	33
1993-07-01	211
1993-10-01	493
1994-01-01	550
1994-04-01	700
1994-07-01	662
1994-10-01	1413
1995-01-01	998
1995-04-01	1112
1995-07-01	1407
1995-10-01	1592
1996-01-01	1972
1996-04-01	2985
1996-07-01	1709
1996-10-01	2169
1997-01-01	2560
1997-04-01	2660
1997-07-01	2919
1997-10-01	2949
1998-01-01	3434
1998-04-01	4179
1998-07-01	3615
1998-10-01	2502
1999-01-01	2062
1999-04-01	2361
1999-07-01	2087
1999-10-01	1957
2000-01-01	2204
2000-04-01	2557
2000-07-01	2339
2000-10-01	2319
2001-01-01	2134
2001-04-01	1475
2001-07-01	1192
2001-10-01	1129
2002-01-01	1134
2002-04-01	682
2002-07-01	568
2002-10-01	636
2003-01-01	1252
2003-04-01	1805
2003-07-01	1574
2003-10-01	1300
2004-01-01	1194
2004-04-01	721
2004-07-01	832
2004-10-01	1071
2005-01-01	1303
2005-04-01	1173
2005-07-01	1002
2005-10-01	1566
2006-01-01	1618
2006-04-01	1496
2006-07-01	1443
2006-10-01	700
2007-01-01	860
2007-04-01	1429
2007-07-01	1627
2007-10-01	2181
2008-01-01	2514
2008-04-01	2618
2008-07-01	2897
2008-10-01	2670
2009-01-01	2500
2009-04-01	2732
2009-07-01	2560
2009-10-01	2163
2010-01-01	2130
2010-04-01	1988
2010-07-01	2643
2010-10-01	2404
2011-01-01	2248
2011-04-01	3511
2011-07-01	3773
2011-10-01	5081
2012-01-01	5155
2012-04-01	5428
2012-07-01	4166
2012-10-01	3636
2013-01-01	4244
2013-04-01	3488
2013-07-01	3567
2013-10-01	3440
2014-01-01	3001
2014-04-01	1848
2014-07-01	1155
2014-10-01	1111
2015-01-01	2058
2015-04-01	2389
2015-07-01	2395
2015-10-01	2283
2016-01-01	2345
2016-04-01	2008
2016-07-01	2389
2016-10-01	3606
2017-01-01	5147
2017-04-01	5160
2017-07-01	3659
2017-10-01	3060
2018-01-01	2588
2018-04-01	3844