| Date | Value |
|---|---|
| Jun 14, 2013 12:24 | 40 ppm |
| May 9, 2013 19:11 | 40 ppm |
| Apr 17, 2013 18:06 | 0.00 ppm |
| Apr 17, 2013 18:05 | 10 ppm |
| Apr 10, 2013 11:43 | 0.00 ppm |
| Mar 25, 2013 10:31 | 0.00 ppm |
| Mar 12, 2013 16:23 | 0.00 ppm |
| Mar 6, 2013 19:10 | 10 ppm |
| Feb 27, 2013 17:09 | 5 ppm |
| Feb 5, 2013 14:08 | 40 ppm |
| Jan 30, 2013 11:49 | 20 ppm |