| Date | Value |
|---|---|
| Oct 5, 2016 12:44 | 1280 ppm |
| Apr 27, 2016 15:31 | 1320 ppm |
| Apr 1, 2016 12:10 | 1320 ppm |
| Mar 19, 2016 19:05 | 1320 ppm |
| Mar 13, 2016 17:33 | 1320 ppm |
| Mar 11, 2016 19:13 | 1360 ppm |
| Mar 10, 2016 20:00 | 1320 ppm |
| Feb 13, 2015 05:15 | 1480 ppm |
| Feb 3, 2015 10:51 | 1480 ppm |