| Date | Value |
|---|---|
| Nov 25, 2014 17:15 | 434 ppm |
| Sep 20, 2014 12:58 | 434 ppm |
| Sep 7, 2014 12:15 | 422 ppm |
| Aug 30, 2014 12:28 | 452 ppm |
| Aug 16, 2014 15:16 | 440 ppm |
| Feb 22, 2014 13:23 | 398 ppm |
| Feb 15, 2014 16:27 | 452 ppm |
| Feb 8, 2014 15:08 | 440 ppm |
| Feb 1, 2014 13:24 | 440 ppm |