| Date | Value |
|---|---|
| Feb 10, 2020 11:48 | 0.02 ppm |
| Nov 9, 2019 18:26 | 0.03 ppm |
| Oct 31, 2019 10:41 | 0.03 ppm |
| Oct 25, 2019 12:26 | 0.06 ppm |
| Oct 19, 2019 10:47 | 0.01 ppm |
| Sep 23, 2019 14:37 | 0.04 ppm |
| Sep 6, 2019 20:07 | 0.02 ppm |
| Aug 28, 2019 22:43 | 0.04 ppm |
| May 5, 2019 18:07 | 0.03 ppm |
| May 4, 2019 10:06 | 0.00 ppm |