| Date | Value |
|---|---|
| Sep 1, 2017 09:16 | 420 ppm |
| Aug 11, 2017 15:54 | 450 ppm |
| Aug 5, 2017 09:33 | 420 ppm |
| Jul 30, 2017 14:33 | 350 ppm |
| Jul 16, 2017 08:26 | 490 ppm |
| Jul 7, 2017 19:40 | 450 ppm |
| Jul 5, 2017 13:11 | 350 ppm |
| May 26, 2017 14:36 | 400 ppm |
| May 12, 2017 11:32 | 420 ppm |
| Apr 8, 2017 12:57 | 420 ppm |
| Mar 31, 2017 18:08 | 400 ppm |
| Mar 24, 2017 15:06 | 430 ppm |
| Mar 17, 2017 17:56 | 450 ppm |
| Mar 7, 2017 17:19 | 400 ppm |