| Date | Value |
|---|---|
| Apr 20, 2019 10:16 | 20 ppm |
| Mar 14, 2019 15:32 | 20 ppm |
| Mar 3, 2019 15:21 | 5 ppm |
| Feb 26, 2019 09:17 | 80 ppm |
| Feb 10, 2019 15:37 | 20 ppm |
| Feb 2, 2019 07:41 | 5 ppm |
| Jan 21, 2019 11:22 | 20 ppm |
| Jan 14, 2019 18:21 | 40 ppm |
| Jan 4, 2019 17:52 | 40 ppm |
| Dec 24, 2018 17:50 | 40 ppm |
| Dec 12, 2018 17:48 | 40 ppm |
| Dec 4, 2018 17:42 | 5 ppm |
| Nov 28, 2018 12:25 | 20 ppm |
| Nov 19, 2018 12:23 | 20 ppm |
| Nov 9, 2018 04:21 | 40 ppm |