| Date | Value |
|---|---|
| Feb 19, 2017 22:09 | 390 ppm |
| Feb 13, 2017 22:40 | 415 ppm |
| Feb 6, 2017 13:54 | 405 ppm |
| Feb 2, 2017 02:34 | 415 ppm |
| Jan 31, 2017 21:57 | 400 ppm |
| Jan 30, 2017 10:36 | 370 ppm |
| Jan 27, 2017 13:27 | 390 ppm |
| Jan 24, 2017 20:43 | 380 ppm |
| Jan 16, 2017 04:00 | 370 ppm |