| Date | Value |
|---|---|
| May 11, 2014 11:28 | 430 ppm |
| May 4, 2014 07:58 | 380 ppm |
| Apr 22, 2014 07:11 | 380 ppm |
| Apr 21, 2014 14:06 | 380 ppm |
| Apr 13, 2014 07:45 | 400 ppm |
| Mar 29, 2014 12:56 | 400 ppm |
| Mar 23, 2014 07:03 | 420 ppm |
| Mar 21, 2014 11:17 | 410 ppm |
| Mar 15, 2014 08:12 | 410 ppm |
| Mar 2, 2014 08:46 | 390 ppm |