| Date | Value |
|---|---|
| Oct 28, 2020 02:40 | 8 ppm |
| Jul 20, 2020 19:04 | 8 ppm |
| Jul 3, 2020 01:44 | 8 ppm |
| May 12, 2020 01:11 | 8 ppm |
| May 3, 2020 19:54 | 4 ppm |
| Apr 12, 2020 02:48 | 8 ppm |
| Apr 1, 2020 01:37 | 8 ppm |
| Mar 27, 2020 00:31 | 4 ppm |
| Mar 25, 2020 03:08 | 4 ppm |
| Mar 23, 2020 15:09 | 4 ppm |
| Mar 23, 2020 03:35 | 4 ppm |