| Date | Value |
|---|---|
| Mar 15, 2015 18:57 | 455 ppm |
| Feb 16, 2015 15:09 | 470 ppm |
| Feb 1, 2015 21:49 | 450 ppm |
| Jan 4, 2015 18:57 | 460 ppm |
| Dec 28, 2014 20:09 | 450 ppm |
| Dec 21, 2014 22:58 | 430 ppm |
| Dec 14, 2014 23:21 | 430 ppm |
| Dec 7, 2014 21:19 | 420 ppm |
| Nov 30, 2014 21:43 | 400 ppm |
| Nov 29, 2014 11:42 | 375 ppm |
| Nov 27, 2014 20:25 | 410 ppm |