| Date | Value |
|---|---|
| Feb 27, 2021 10:17 | 450 ppm |
| Dec 6, 2020 10:08 | 440 ppm |
| Oct 22, 2020 10:28 | 400 ppm |
| Aug 30, 2020 08:41 | 350 ppm |
| Aug 9, 2020 09:21 | 350 ppm |
| Aug 2, 2020 08:33 | 360 ppm |
| Jul 26, 2020 08:46 | 380 ppm |
| Jul 18, 2020 07:53 | 390 ppm |
| Jul 12, 2020 13:36 | 420 ppm |
| Jul 4, 2020 15:00 | 380 ppm |
| Jun 27, 2020 09:13 | 390 ppm |
| Jun 20, 2020 09:20 | 500 ppm |
| Jun 14, 2020 08:34 | 430 ppm |