| Date | Value |
|---|---|
| May 11, 2014 08:10 | 1380 ppm |
| May 4, 2014 07:18 | 1320 ppm |
| Apr 22, 2014 07:11 | 1275 ppm |
| Apr 21, 2014 14:15 | 1275 ppm |
| Apr 13, 2014 07:23 | 1280 ppm |
| Mar 29, 2014 12:29 | 1300 ppm |
| Mar 23, 2014 07:04 | 1350 ppm |
| Mar 21, 2014 11:16 | 1390 ppm |
| Mar 15, 2014 08:12 | 1390 ppm |
| Mar 2, 2014 08:45 | 1260 ppm |