| Date | Value |
|---|---|
| Jun 11, 2017 20:18 | 0.00 ppm |
| Feb 1, 2017 19:41 | 0.05 ppm |
| Dec 21, 2016 10:16 | 0.00 ppm |
| Dec 6, 2016 20:20 | 0.00 ppm |
| Oct 30, 2016 11:31 | 0.00 ppm |
| Sep 20, 2016 00:26 | 0.10 ppm |
| Aug 28, 2016 16:13 | 0.20 ppm |
| Apr 19, 2016 19:01 | 0.00 ppm |
| Mar 24, 2016 18:31 | 0.00 ppm |