EDIT: for reference here are my data:
s01 s02 s03 s04
01/01/1999 3.00E+10 121.8628 1.94E+12 1.457384
01/04/1999 3.01E+10 126.09073 1.95E+12 1.520934
01/07/1999 3.13E+10 125.06515 1.97E+12 1.527138
01/10/1999 3.21E+10 126.99142 2.00E+12 1.571251
01/01/2000 3.27E+10 126.9887 2.02E+12 1.628555
01/04/2000 3.35E+10 124.37588 2.04E+12 1.639844
01/07/2000 3.44E+10 119.11178 2.05E+12 1.633594
01/10/2000 3.49E+10 113.61613 2.06E+12 1.667029
01/01/2001 3.53E+10 106.50717 2.13E+12 1.581423
01/04/2001 3.57E+10 102.98313 2.13E+12 1.628003
01/07/2001 3.58E+10 87.99769 2.13E+12 1.615208
01/10/2001 3.64E+10 81.14929 2.14E+12 1.611063
01/01/2002 3.74E+10 87.58887 2.14E+12 1.626313
01/04/2002 3.76E+10 91.04958 2.15E+12 1.592302
01/07/2002 3.85E+10 73.95882 2.16E+12 1.574734
01/10/2002 3.88E+10 65.37162 2.16E+12 1.571639
01/01/2003 3.83E+10 63.21862 2.16E+12 1.493654
01/04/2003 3.85E+10 66.92185 2.16E+12 1.425593
01/07/2003 3.91E+10 63.98062 2.17E+12 1.430009
01/10/2003 4.12E+10 75.31742 2.18E+12 1.433381
01/01/2004 4.11E+10 86.14754 2.20E+12 1.470845
01/04/2004 4.19E+10 90.64507 2.21E+12 1.499202
01/07/2004 4.19E+10 95.21745 2.21E+12 1.487668
01/10/2004 4.28E+10 98.69023 2.22E+12 1.438778
01/01/2005 4.34E+10 103.51991 2.23E+12 1.442369
01/04/2005 4.43E+10 98.09163 2.24E+12 1.474367
01/07/2005 4.45E+10 89.34391 2.26E+12 1.463475
01/10/2005 4.57E+10 92.3905 2.27E+12 1.470589
01/01/2006 4.61E+10 100.46526 2.29E+12 1.456973
01/04/2006 4.64E+10 93.49614 2.31E+12 1.454008
01/07/2006 4.75E+10 87.41035 2.33E+12 1.471341
01/10/2006 4.76E+10 88.11269 2.35E+12 1.485422
01/01/2007 4.98E+10 85.51956 2.38E+12 1.491547
01/04/2007 4.92E+10 83.95523 2.39E+12 1.473238
01/07/2007 4.81E+10 73.64344 2.40E+12 1.470523
01/10/2007 5.02E+10 65.87211 2.42E+12 1.412875
01/01/2008 4.87E+10 64.58933 2.44E+12 1.321165
01/04/2008 4.77E+10 49.00284 2.43E+12 1.261533
01/07/2008 4.75E+10 42.66211 2.41E+12 1.258634
01/10/2008 4.57E+10 45.64976 2.37E+12 1.195684
01/01/2009 4.55E+10 45.97453 2.32E+12 1.101032
01/04/2009 4.55E+10 48.54799 2.31E+12 1.13892
01/07/2009 4.49E+10 49.28164 2.32E+12 1.147522
01/10/2009 4.49E+10 53.70312 2.33E+12 1.105827
01/01/2010 4.55E+10 61.94103 2.34E+12 1.126911
01/04/2010 4.59E+10 66.2847 2.37E+12 1.174664
01/07/2010 4.63E+10 60.00519 2.38E+12 1.19952
01/10/2010 4.63E+10 46.94403 2.39E+12 1.16393
01/01/2011 4.73E+10 52.82631 2.41E+12 1.171049
01/04/2011 4.75E+10 57.85739 2.41E+12 1.132937
01/07/2011 4.73E+10 55 2.41E+12 1.140152
01/10/2011 4.73E+10 57.66075 2.40E+12 1.166011
01/01/2012 4.72E+10 58.06121 2.40E+12 1.19852
01/04/2012 4.76E+10 61.93385 2.39E+12 1.234437
01/07/2012 4.70E+10 65.9692 2.39E+12 1.263261
01/10/2012 4.76E+10 58.12565 2.38E+12 1.23845
01/01/2013 4.68E+10 61.19564 2.37E+12 1.175077
01/04/2013 4.77E+10 63.54526 2.38E+12 1.175606
01/07/2013 4.92E+10 69.36935 2.39E+12 1.17076
01/10/2013 4.88E+10 75.67541 2.40E+12 1.189011
01/01/2014 5.06E+10 84.37443 2.41E+12 1.207956
01/04/2014 5.20E+10 82.55904 2.41E+12 1.22783
01/07/2014 5.26E+10 89.75978 2.42E+12 1.259912
01/10/2014 5.33E+10 87.11057 2.43E+12 1.267081
01/01/2015 6.47E+10 98.34575 2.46E+12 1.346294
01/04/2015 6.34E+10 100.01053 2.47E+12 1.386315
01/07/2015 6.67E+10 100.4896 2.48E+12 1.393723
01/10/2015 6.69E+10 102.76665 2.49E+12 1.386148
01/01/2016 6.65E+10 104.98214 2.50E+12 1.298074
01/04/2016 6.69E+10 101.38637 2.51E+12 1.270157
01/07/2016 6.88E+10 101.43875 2.52E+12 1.176277
01/10/2016 7.28E+10 97.10191 2.54E+12 1.151544
01/01/2017 7.09E+10 101.9 2.55E+12 1.162719