| Date | Value |
|---|---|
| May 28, 2019 08:20 | 450 ppm |
| Apr 26, 2019 17:56 | 430 ppm |
| Apr 24, 2019 19:06 | 400 ppm |
| Apr 20, 2019 21:10 | 400 ppm |
| Apr 19, 2019 20:06 | 430 ppm |
| Apr 18, 2019 18:41 | 425 ppm |
| Apr 16, 2019 02:31 | 425 ppm |
| Apr 15, 2019 04:03 | 400 ppm |
| Apr 10, 2019 01:57 | 410 ppm |
| Apr 3, 2019 18:04 | 440 ppm |
| Apr 1, 2019 17:28 | 440 ppm |