| Date | Value |
|---|---|
| Nov 22, 2016 14:52 | 0.00 ppm |
| Dec 20, 2015 12:45 | 5 ppm |
| Jun 10, 2015 17:02 | 2 ppm |
| May 14, 2015 14:00 | 0.00 ppm |
| Apr 19, 2015 10:48 | 25 ppm |
| Feb 28, 2015 11:04 | 22 ppm |
| Feb 1, 2015 11:30 | 21 ppm |
| Dec 7, 2014 08:31 | 15 ppm |
| Nov 30, 2014 15:39 | 3 ppm |
| Oct 30, 2014 16:39 | 2 ppm |
| Mar 11, 2014 16:40 | 0.00 ppm |