| Date | Value |
|---|---|
| Nov 20, 2013 18:55 | 1560 ppm |
| Nov 19, 2013 16:56 | 1470 ppm |
| Oct 16, 2013 17:01 | 1410 ppm |
| May 29, 2013 12:26 | 1500 ppm |
| Apr 15, 2013 11:53 | 1530 ppm |
| Feb 26, 2013 13:26 | 1500 ppm |
| Feb 5, 2013 16:54 | 1300 ppm |
| Jan 27, 2013 14:41 | 1300 ppm |
| Jan 11, 2013 14:21 | 1200 ppm |
| Dec 28, 2012 11:27 | 1290 ppm |
| Dec 19, 2012 19:50 | 1320 ppm |
| Dec 12, 2012 19:06 | 1470 ppm |