| Date | Value |
|---|---|
| Oct 12, 2013 04:38 | 1360 ppm |
| Sep 29, 2013 07:08 | 1360 ppm |
| Sep 23, 2013 04:30 | 1340 ppm |
| Sep 15, 2013 09:27 | 1320 ppm |
| Sep 14, 2013 04:42 | 1260 ppm |
| Sep 10, 2013 15:30 | 1300 ppm |
| Sep 8, 2013 09:53 | 1360 ppm |
| Sep 5, 2013 11:39 | 1360 ppm |
| Aug 30, 2013 10:53 | 1250 ppm |