| Date | Value |
|---|---|
| Feb 24, 2017 17:41 | 1600 ppm |
| Feb 10, 2017 19:01 | 1600 ppm |
| Feb 3, 2017 14:16 | 1400 ppm |
| Jan 21, 2017 15:06 | 1500 ppm |
| Jan 14, 2017 13:13 | 1600 ppm |
| Dec 26, 2016 13:41 | 1600 ppm |
| Dec 16, 2016 16:20 | 1600 ppm |
| Dec 4, 2016 11:06 | 1600 ppm |
| Nov 27, 2016 08:44 | 1600 ppm |
| Nov 24, 2016 12:54 | 1200 ppm |
| Nov 20, 2016 18:15 | 920 ppm |