| Date | Value |
|---|---|
| Jul 10, 2016 14:23 | 18 ppb |
| May 15, 2016 09:50 | 0 ppb |
| May 3, 2016 18:27 | 0 ppb |
| Apr 2, 2016 15:57 | 19 ppb |
| Jan 16, 2016 16:10 | 10 ppb |
| Oct 10, 2015 11:06 | 1 ppb |
| Sep 7, 2015 12:45 | 0 ppb |
| Aug 23, 2015 14:22 | 0 ppb |
| Aug 8, 2015 16:55 | 11 ppb |
| Aug 1, 2015 13:16 | 0 ppb |
| Jun 21, 2015 17:07 | 0 ppb |
| Jun 14, 2015 16:13 | 0 ppb |
| Jun 6, 2015 18:22 | 10 ppb |
| Jun 2, 2015 20:01 | 31 ppb |