| Date | Value |
|---|---|
| Mar 9, 2018 19:16 | 1300 ppm |
| Jan 25, 2018 20:00 | 1300 ppm |
| Jan 14, 2018 11:40 | 1300 ppm |
| Jan 7, 2018 19:25 | 1300 ppm |
| Dec 31, 2017 20:54 | 1260 ppm |
| Dec 16, 2017 09:21 | 1360 ppm |
| Dec 9, 2017 10:30 | 1320 ppm |
| Dec 2, 2017 19:42 | 1360 ppm |
| Nov 12, 2017 19:42 | 1380 ppm |