| Date | Value |
|---|---|
| Feb 21, 2022 17:45 | 19 ppb |
| Dec 7, 2021 10:59 | 6 ppb |
| Oct 10, 2021 19:38 | 13 ppb |
| Jun 7, 2021 13:01 | 6.56 ppb |
| Mar 21, 2021 15:16 | 12 ppb |
| Jan 21, 2021 15:45 | 17 ppb |
| Jul 2, 2020 18:56 | 3.88 ppb |
| Apr 14, 2020 18:50 | 5.25 ppb |
| Feb 10, 2020 14:34 | 19 ppb |
| Dec 5, 2019 10:38 | 18 ppb |