| Date | Value |
|---|---|
| Feb 24, 2017 17:37 | 300 ppm |
| Feb 10, 2017 18:55 | 450 ppm |
| Feb 3, 2017 17:10 | 450 ppm |
| Jan 21, 2017 12:02 | 450 ppm |
| Jan 14, 2017 13:09 | 490 ppm |
| Dec 26, 2016 13:37 | 500 ppm |
| Dec 16, 2016 16:15 | 500 ppm |
| Dec 4, 2016 10:51 | 490 ppm |
| Nov 27, 2016 05:33 | 500 ppm |
| Nov 24, 2016 12:48 | 450 ppm |
| Nov 20, 2016 17:57 | 405 ppm |