Quarter	Millions of US Dollars
1971-10-01	0
1972-01-01	0
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	20
1979-07-01	20
1979-10-01	20
1980-01-01	20
1980-04-01	0
1980-07-01	30
1980-10-01	55
1981-01-01	70
1981-04-01	123
1981-07-01	137
1981-10-01	137
1982-01-01	214
1982-04-01	183
1982-07-01	139
1982-10-01	134
1983-01-01	57
1983-04-01	32
1983-07-01	59
1983-10-01	48
1984-01-01	43
1984-04-01	132
1984-07-01	154
1984-10-01	255
1985-01-01	346
1985-04-01	293
1985-07-01	296
1985-10-01	323
1986-01-01	226
1986-04-01	197
1986-07-01	178
1986-10-01	31
1987-01-01	111
1987-04-01	185
1987-07-01	237
1987-10-01	342
1988-01-01	270
1988-04-01	181
1988-07-01	167
1988-10-01	345
1989-01-01	362
1989-04-01	405
1989-07-01	363
1989-10-01	131
1990-01-01	149
1990-04-01	190
1990-07-01	262
1990-10-01	331
1991-01-01	312
1991-04-01	423
1991-07-01	369
1991-10-01	369
1992-01-01	349
1992-04-01	146
1992-07-01	117
1992-10-01	183
1993-01-01	267
1993-04-01	423
1993-07-01	1889
1993-10-01	1904
1994-01-01	2741
1994-04-01	3213
1994-07-01	3844
1994-10-01	3994
1995-01-01	2619
1995-04-01	2087
1995-07-01	2820
1995-10-01	3585
1996-01-01	5086
1996-04-01	4890
1996-07-01	3602
1996-10-01	4832
1997-01-01	4313
1997-04-01	5016
1997-07-01	5166
1997-10-01	6348
1998-01-01	6429
1998-04-01	8579
1998-07-01	9055
1998-10-01	8829
1999-01-01	10479
1999-04-01	8871
1999-07-01	10109
1999-10-01	10058
2000-01-01	9918
2000-04-01	11296
2000-07-01	11022
2000-10-01	12642
2001-01-01	13636
2001-04-01	15926
2001-07-01	16796
2001-10-01	13711
2002-01-01	13508
2002-04-01	13640
2002-07-01	16643
2002-10-01	18706
2003-01-01	22693
2003-04-01	22362
2003-07-01	20180
2003-10-01	22013
2004-01-01	19068
2004-04-01	21088
2004-07-01	20113
2004-10-01	24322
2005-01-01	24884
2005-04-01	26002
2005-07-01	28344
2005-10-01	27409
2006-01-01	29018
2006-04-01	28739
2006-07-01	29541
2006-10-01	31380
2007-01-01	37855
2007-04-01	42414
2007-07-01	42551
2007-10-01	43253
2008-01-01	39426
2008-04-01	44668
2008-07-01	45682
2008-10-01	45311
2009-01-01	32536
2009-04-01	31821
2009-07-01	34484
2009-10-01	37651
2010-01-01	41280
2010-04-01	39906
2010-07-01	44296
2010-10-01	43343
2011-01-01	39616
2011-04-01	43772
2011-07-01	42079
2011-10-01	39304
2012-01-01	42147
2012-04-01	43695
2012-07-01	48064
2012-10-01	59744
2013-01-01	60304
2013-04-01	65081
2013-07-01	68313
2013-10-01	70854
2014-01-01	71725
2014-04-01	72106
2014-07-01	74630
2014-10-01	71259
2015-01-01	65167
2015-04-01	57268
2015-07-01	48637
2015-10-01	47241
2016-01-01	60939
2016-04-01	65204
2016-07-01	65564
2016-10-01	66994
2017-01-01	67298
2017-04-01	62652
2017-07-01	63799
2017-10-01	60654
2018-01-01	62023
2018-04-01	66280