observation_date	LOG
1975-01-01	3.884783967
1975-04-01	3.871122243
1975-07-01	3.853126594
1975-10-01	3.864652598
1976-01-01	3.870526323
1976-04-01	3.877937037
1976-07-01	3.881798483
1976-10-01	3.885774779
1977-01-01	3.902749369
1977-04-01	3.917342167
1977-07-01	3.928283526
1977-10-01	3.955542657
1978-01-01	3.974659719
1978-04-01	3.986488615
1978-07-01	3.999135849
1978-10-01	4.01314205
1979-01-01	4.035289596
1979-04-01	4.037519371
1979-07-01	4.036381125
1979-10-01	4.036873208
1980-01-01	4.025856521
1980-04-01	4.005760681
1980-07-01	4.001711167
1980-10-01	3.99351604
1981-01-01	3.983220342
1981-04-01	3.975298103
1981-07-01	3.962890445
1981-10-01	3.953752511
1982-01-01	3.949692635
1982-04-01	3.943554346
1982-07-01	3.913662686
1982-10-01	3.908554676
1983-01-01	3.921993583
1983-04-01	3.92612193
1983-07-01	3.924359015
1983-10-01	3.924029842
1984-01-01	3.926636027
1984-04-01	3.926658352
1984-07-01	3.929732694
1984-10-01	3.929532631
1985-01-01	3.938217207
1985-04-01	3.940609553
1985-07-01	3.948814625
1985-10-01	3.961032184
1986-01-01	3.974963535
1986-04-01	4.005489867
1986-07-01	4.020447316
1986-10-01	4.036332496
1987-01-01	4.052566625
1987-04-01	4.057133069
1987-07-01	4.068230319
1987-10-01	4.073604809
1988-01-01	4.086535412
1988-04-01	4.09049429
1988-07-01	4.097994714
1988-10-01	4.101666554
1989-01-01	4.112077942
1989-04-01	4.110860547
1989-07-01	4.107917625
1989-10-01	4.1066098
1990-01-01	4.100344319
1990-04-01	4.093568466
1990-07-01	4.080185489
1990-10-01	4.050970417
1991-01-01	4.032411197
1991-04-01	4.023342065
1991-07-01	4.022831211
1991-10-01	4.014059224
1992-01-01	4.008977544
1992-04-01	4.002302632
1992-07-01	3.994242373
1992-10-01	3.986473454
1993-01-01	3.986201101
1993-04-01	3.978382784
1993-07-01	3.981957262
1993-10-01	3.979688068
1994-01-01	3.984566338
1994-04-01	3.981468059
1994-07-01	3.982398568
1994-10-01	3.980899928
1995-01-01	3.980048454
1995-04-01	3.972438489
1995-07-01	3.971960795
1995-10-01	3.970893248
1996-01-01	3.970634019
1996-04-01	3.965584998
1996-07-01	3.967282945
1996-10-01	3.964446425
1997-01-01	3.966215926
1997-04-01	3.967390386
1997-07-01	3.973870994
1997-10-01	3.976484172
1998-01-01	3.993397651
1998-04-01	4.002116806
1998-07-01	4.013774074
1998-10-01	4.024371245
1999-01-01	4.038652975
1999-04-01	4.043958661
1999-07-01	4.059863648
1999-10-01	4.070681938
2000-01-01	4.087210168
2000-04-01	4.095705768
2000-07-01	4.107471757
2000-10-01	4.122488832
2001-01-01	4.138928746
2001-04-01	4.144954563
2001-07-01	4.157914304
2001-10-01	4.172697605
2002-01-01	4.191910806
2002-04-01	4.197561514
2002-07-01	4.22294758
2002-10-01	4.239153819
2003-01-01	4.258430782
2003-04-01	4.265679252
2003-07-01	4.286974714
2003-10-01	4.308656436
2004-01-01	4.33709309
2004-04-01	4.356436013
2004-07-01	4.380837967
2004-10-01	4.401672613
2005-01-01	4.43767266
2005-04-01	4.455207368
2005-07-01	4.482603465
2005-10-01	4.492812916
2006-01-01	4.521152535
2006-04-01	4.516108434
2006-07-01	4.499427397
2006-10-01	4.508526114
2007-01-01	4.512603059
2007-04-01	4.483564889
2007-07-01	4.454307438
2007-10-01	4.437255964
2008-01-01	4.407091248
2008-04-01	4.361400898
2008-07-01	4.309069587
2008-10-01	4.291987133
2009-01-01	4.273352186
2009-04-01	4.239693861
2009-07-01	4.233014398
2009-10-01	4.22533855
2010-01-01	4.21986625
2010-04-01	4.206908133
2010-07-01	4.19715149
2010-10-01	4.176831135
2011-01-01	4.163111879
2011-04-01	4.131130071
2011-07-01	4.124549225
2011-10-01	4.109520398
2012-01-01	4.09882718
2012-04-01	4.102561286
2012-07-01	4.124494546
2012-10-01	4.128412778
2013-01-01	4.155422068
2013-04-01	4.177260175
2013-07-01	4.198994197
2013-10-01	4.222392001
2014-01-01	4.238113039
2014-04-01	4.233680444
2014-07-01	4.235185655
2014-10-01	4.251300517
2015-01-01	4.280053513
2015-04-01	4.277480105
2015-07-01	4.278114867
2015-10-01	4.297623257
2016-01-01	4.317448718
2016-04-01	4.315615322
2016-07-01	4.318977548
2016-10-01	4.332016904
2017-01-01	4.346443687
2017-04-01	4.349453877
