Quarter	Millions of US Dollars
1978-01-01	25
1978-04-01	73
1978-07-01	79
1978-10-01	79
1979-01-01	104
1979-04-01	183
1979-07-01	248
1979-10-01	242
1980-01-01	236
1980-04-01	296
1980-07-01	300
1980-10-01	304
1981-01-01	297
1981-04-01	284
1981-07-01	324
1981-10-01	334
1982-01-01	353
1982-04-01	346
1982-07-01	336
1982-10-01	364
1983-01-01	356
1983-04-01	355
1983-07-01	462
1983-10-01	466
1984-01-01	580
1984-04-01	482
1984-07-01	512
1984-10-01	503
1985-01-01	903
1985-04-01	946
1985-07-01	1029
1985-10-01	1362
1986-01-01	1422
1986-04-01	1416
1986-07-01	1393
1986-10-01	1376
1987-01-01	1426
1987-04-01	1422
1987-07-01	1425
1987-10-01	1542
1988-01-01	1526
1988-04-01	1402
1988-07-01	1628
1988-10-01	1708
1989-01-01	1687
1989-04-01	1674
1989-07-01	1772
1989-10-01	1770
1990-01-01	1671
1990-04-01	1432
1990-07-01	1504
1990-10-01	1449
1991-01-01	1261
1991-04-01	1249
1991-07-01	1111
1991-10-01	1137
1992-01-01	1348
1992-04-01	1336
1992-07-01	1474
1992-10-01	1449
1993-01-01	1981
1993-04-01	2158
1993-07-01	3447
1993-10-01	4623
1994-01-01	6258
1994-04-01	6457
1994-07-01	7010
1994-10-01	7282
1995-01-01	7681
1995-04-01	7958
1995-07-01	8344
1995-10-01	8743
1996-01-01	10005
1996-04-01	10860
1996-07-01	12624
1996-10-01	13568
1997-01-01	14117
1997-04-01	15411
1997-07-01	15425
1997-10-01	15049
1998-01-01	14759
1998-04-01	14721
1998-07-01	14745
1998-10-01	15146
1999-01-01	14559
1999-04-01	14470
1999-07-01	13992
1999-10-01	13984
2000-01-01	13645
2000-04-01	13824
2000-07-01	13156
2000-10-01	12963
2001-01-01	12083
2001-04-01	12050
2001-07-01	10958
2001-10-01	10267
2002-01-01	9773
2002-04-01	9630
2002-07-01	10529
2002-10-01	10211
2003-01-01	10189
2003-04-01	10034
2003-07-01	9624
2003-10-01	9217
2004-01-01	7868
2004-04-01	8509
2004-07-01	8941
2004-10-01	9306
2005-01-01	9464
2005-04-01	10818
2005-07-01	10302
2005-10-01	10482
2006-01-01	10274
2006-04-01	10962
2006-07-01	11434
2006-10-01	11264
2007-01-01	10704
2007-04-01	9635
2007-07-01	9659
2007-10-01	9442
2008-01-01	9505
2008-04-01	9296
2008-07-01	9258
2008-10-01	8984
2009-01-01	8698
2009-04-01	8318
2009-07-01	8145
2009-10-01	7833
2010-01-01	7602
2010-04-01	7316
2010-07-01	8149
2010-10-01	9267
2011-01-01	9571
2011-04-01	10227
2011-07-01	9836
2011-10-01	10194
2012-01-01	11637
2012-04-01	12109
2012-07-01	14420
2012-10-01	16476
2013-01-01	17487
2013-04-01	17263
2013-07-01	17790
2013-10-01	18418
2014-01-01	18739
2014-04-01	21512
2014-07-01	21128
2014-10-01	20939
2015-01-01	20990
2015-04-01	20340
2015-07-01	19808
2015-10-01	19355
2016-01-01	19336
2016-04-01	19990
2016-07-01	20833
2016-10-01	20159
2017-01-01	20895
2017-04-01	20643
2017-07-01	22700
2017-10-01	20941
2018-01-01	21163
2018-04-01	22348