Quarter	Millions of US Dollars
1972-01-01	49
1972-04-01	119
1972-07-01	129
1972-10-01	214
1973-01-01	214
1973-04-01	350
1973-07-01	388
1973-10-01	683
1974-01-01	776
1974-04-01	1140
1974-07-01	1170
1974-10-01	1242
1975-01-01	1306
1975-04-01	1361
1975-07-01	1407
1975-10-01	1407
1976-01-01	1468
1976-04-01	1524
1976-07-01	1560
1976-10-01	1639
1977-01-01	1756
1977-04-01	1807
1977-07-01	1851
1977-10-01	1919
1978-01-01	1983
1978-04-01	2062
1978-07-01	2124
1978-10-01	2224
1979-01-01	2224
1979-04-01	2224
1979-07-01	2224
1979-10-01	2224
1980-01-01	2224
1980-04-01	2224
1980-07-01	2224
1980-10-01	2224
1981-01-01	2224
1981-04-01	2224
1981-07-01	2224
1981-10-01	2224
1982-01-01	2224
1982-04-01	2224
1982-07-01	2224
1982-10-01	2224
1983-01-01	2224
1983-04-01	2224
1983-07-01	2224
1983-10-01	2124
1984-01-01	2124
1984-04-01	2124
1984-07-01	2124
1984-10-01	2124
1985-01-01	2124
1985-04-01	1989
1985-07-01	1951
1985-10-01	1656
1986-01-01	1562
1986-04-01	1499
1986-07-01	1469
1986-10-01	1396
1987-01-01	1283
1987-04-01	1158
1987-07-01	1103
1987-10-01	1017
1988-01-01	956
1988-04-01	900
1988-07-01	864
1988-10-01	786
1989-01-01	668
1989-04-01	573
1989-07-01	573
1989-10-01	506
1990-01-01	441
1990-04-01	362
1990-07-01	300
1990-10-01	300
1991-01-01	300
1991-04-01	1249
1991-07-01	1249
1991-10-01	1249
1992-01-01	1249
1992-04-01	1249
1992-07-01	1249
1992-10-01	1249
1993-01-01	1249
1993-04-01	1249
1993-07-01	1249
1993-10-01	1249
1994-01-01	1249
1994-04-01	949
1994-07-01	949
1994-10-01	949
1995-01-01	949
1995-04-01	949
1995-07-01	949
1995-10-01	1149
1996-01-01	1149
1996-04-01	1149
1996-07-01	1149
1996-10-01	1349
1997-01-01	1349
1997-04-01	1349
1997-07-01	1514
1997-10-01	1503
1998-01-01	1500
1998-04-01	1408
1998-07-01	1411
1998-10-01	1690
1999-01-01	1682
1999-04-01	2092
1999-07-01	2130
1999-10-01	2273
2000-01-01	2749
2000-04-01	2737
2000-07-01	2696
2000-10-01	2709
2001-01-01	2669
2001-04-01	2655
2001-07-01	2693
2001-10-01	2617
2002-01-01	2956
2002-04-01	3103
2002-07-01	3089
2002-10-01	3151
2003-01-01	3181
2003-04-01	3976
2003-07-01	4025
2003-10-01	4877
2004-01-01	5360
2004-04-01	6335
2004-07-01	6349
2004-10-01	7237
2005-01-01	7164
2005-04-01	7072
2005-07-01	7057
2005-10-01	7704
2006-01-01	7754
2006-04-01	7134
2006-07-01	7121
2006-10-01	8518
2007-01-01	8536
2007-04-01	8555
2007-07-01	8473
2007-10-01	8033
2008-01-01	8156
2008-04-01	8151
2008-07-01	7965
2008-10-01	7886
2009-01-01	8780
2009-04-01	8865
2009-07-01	8898
2009-10-01	8882
2010-01-01	10323
2010-04-01	10250
2010-07-01	10569
2010-10-01	10501
2011-01-01	10820
2011-04-01	10875
2011-07-01	11057
2011-10-01	10929
2012-01-01	12404
2012-04-01	12028
2012-07-01	11710
2012-10-01	11769
2013-01-01	13672
2013-04-01	12985
2013-07-01	13089
2013-10-01	13157
2014-01-01	14726
2014-04-01	14681
2014-07-01	14270
2014-10-01	14098
2015-01-01	13572
2015-04-01	13742
2015-07-01	13742
2015-10-01	12803
2016-01-01	14448
2016-04-01	14354
2016-07-01	14367
2016-10-01	13374
2017-01-01	15827
2017-04-01	16210
2017-07-01	16424
2017-10-01	16520
2018-01-01	18698
2018-04-01	18341