Quarter	Millions of US Dollars
1968-01-01	60
1968-04-01	120
1968-07-01	120
1968-10-01	120
1969-01-01	120
1969-04-01	120
1969-07-01	120
1969-10-01	120
1970-01-01	120
1970-04-01	120
1970-07-01	120
1970-10-01	120
1971-01-01	120
1971-04-01	120
1971-07-01	120
1971-10-01	120
1972-01-01	167
1972-04-01	272
1972-07-01	270
1972-10-01	300
1973-01-01	356
1973-04-01	373
1973-07-01	369
1973-10-01	454
1974-01-01	488
1974-04-01	511
1974-07-01	545
1974-10-01	626
1975-01-01	716
1975-04-01	780
1975-07-01	825
1975-10-01	873
1976-01-01	956
1976-04-01	1066
1976-07-01	1113
1976-10-01	1219
1977-01-01	1227
1977-04-01	1595
1977-07-01	1666
1977-10-01	1830
1978-01-01	2073
1978-04-01	2269
1978-07-01	2605
1978-10-01	2687
1979-01-01	2678
1979-04-01	2769
1979-07-01	2933
1979-10-01	2886
1980-01-01	2629
1980-04-01	2847
1980-07-01	2885
1980-10-01	2807
1981-01-01	2660
1981-04-01	2608
1981-07-01	2755
1981-10-01	2894
1982-01-01	2864
1982-04-01	2795
1982-07-01	3238
1982-10-01	3748
1983-01-01	4711
1983-04-01	5370
1983-07-01	5346
1983-10-01	6074
1984-01-01	7021
1984-04-01	7073
1984-07-01	7384
1984-10-01	7849
1985-01-01	8405
1985-04-01	9021
1985-07-01	10406
1985-10-01	11589
1986-01-01	13677
1986-04-01	17734
1986-07-01	20691
1986-10-01	23244
1987-01-01	28032
1987-04-01	29703
1987-07-01	31985
1987-10-01	35612
1988-01-01	37050
1988-04-01	37170
1988-07-01	38565
1988-10-01	43009
1989-01-01	42899
1989-04-01	44088
1989-07-01	47161
1989-10-01	51001
1990-01-01	52832
1990-04-01	55046
1990-07-01	59641
1990-10-01	61182
1991-01-01	56857
1991-04-01	57345
1991-07-01	62670
1991-10-01	71505
1992-01-01	70513
1992-04-01	78860
1992-07-01	85420
1992-10-01	82756
1993-01-01	87284
1993-04-01	94199
1993-07-01	100319
1993-10-01	105115
1994-01-01	120423
1994-04-01	130447
1994-07-01	140813
1994-10-01	151191
1995-01-01	174641
1995-04-01	189390
1995-07-01	197519
1995-10-01	212057
1996-01-01	229088
1996-04-01	241735
1996-07-01	258130
1996-10-01	277065
1997-01-01	291410
1997-04-01	309826
1997-07-01	320336
1997-10-01	324488
1998-01-01	345673
1998-04-01	368352
1998-07-01	401463
1998-10-01	408707
1999-01-01	428853
1999-04-01	447973
1999-07-01	512971
1999-10-01	524200
2000-01-01	554502
2000-04-01	603499
2000-07-01	621429
2000-10-01	681684
2001-01-01	701013
2001-04-01	713646
2001-07-01	762671
2001-10-01	765087
2002-01-01	794835
2002-04-01	916343
2002-07-01	940638
2002-10-01	1000334
2003-01-01	1074895
2003-04-01	1145183
2003-07-01	1180917
2003-10-01	1303607
2004-01-01	1325510
2004-04-01	1360460
2004-07-01	1441117
2004-10-01	1588560
2005-01-01	1588962
2005-04-01	1563154
2005-07-01	1544735
2005-10-01	1563088
2006-01-01	1662844
2006-04-01	1790604
2006-07-01	1833861
2006-10-01	1940507
2007-01-01	2009820
2007-04-01	2101512
2007-07-01	2184846
2007-10-01	2266121
2008-01-01	2393495
2008-04-01	2420812
2008-07-01	2217365
2008-10-01	2159190
2009-01-01	2072006
2009-04-01	2189603
2009-07-01	2223131
2009-10-01	2169786
2010-01-01	2073033
2010-04-01	1925472
2010-07-01	2084416
2010-10-01	2021815
2011-01-01	2101098
2011-04-01	2137833
2011-07-01	2069711
2011-10-01	2033738
2012-01-01	2096762
2012-04-01	2029046
2012-07-01	2035350
2012-10-01	2075287
2013-01-01	2014024
2013-04-01	2026130
2013-07-01	2046465
2013-10-01	2050460
2014-01-01	2036648
2014-04-01	2050142
2014-07-01	1943594
2014-10-01	1900116
2015-01-01	1768701
2015-04-01	1815490
2015-07-01	1795248
2015-10-01	1716223
2016-01-01	1790284
2016-04-01	1760931
2016-07-01	1786296
2016-10-01	1709893
2017-01-01	1760492
2017-04-01	1836919
2017-07-01	1886039
2017-10-01	1902276
2018-01-01	1957449
2018-04-01	1899838