| Date | Value |
|---|---|
| Feb 13, 2018 05:56 | 370 ppm |
| Nov 15, 2017 21:47 | 400 ppm |
| Aug 25, 2017 20:16 | 410 ppm |
| Jul 18, 2017 21:45 | 380 ppm |
| Apr 24, 2017 21:09 | 470 ppm |
| Apr 4, 2017 20:15 | 420 ppm |
| Mar 16, 2017 19:34 | 450 ppm |
| Mar 7, 2017 20:41 | 450 ppm |
| Feb 28, 2017 21:49 | 440 ppm |
| Feb 23, 2017 21:12 | 440 ppm |
| Feb 20, 2017 21:43 | 440 ppm |
| Feb 15, 2017 22:20 | 400 ppm |
| Feb 11, 2017 15:45 | 390 ppm |
| Feb 8, 2017 10:02 | 410 ppm |
| Feb 3, 2017 12:06 | 380 ppm |