| Date | Value |
|---|---|
| Jan 24, 2016 12:41 | 0.08 ppm |
| Sep 16, 2015 08:23 | 0.23 ppm |
| Dec 11, 2014 12:35 | 0.06 ppm |
| Jul 10, 2014 10:37 | 0.03 ppm |
| Jun 7, 2014 19:40 | 0.08 ppm |
| Feb 20, 2014 10:35 | 0.25 ppm |
| Dec 12, 2013 10:18 | 0.25 ppm |
| Sep 20, 2013 10:31 | 0.25 ppm |
| Sep 8, 2013 21:21 | 0.25 ppm |