| Date | Value |
|---|---|
| Jul 14, 2014 08:13 | 2 ppm |
| Jul 1, 2014 08:27 | 2 ppm |
| Jun 29, 2014 12:19 | 2 ppm |
| Jun 21, 2014 06:35 | 4 ppm |
| May 13, 2014 02:43 | 2 ppm |
| May 12, 2014 07:46 | 2 ppm |
| May 1, 2014 07:10 | 5 ppm |
| Apr 17, 2014 07:58 | 2 ppm |
| Apr 14, 2014 06:39 | 2 ppm |
| Apr 13, 2014 06:43 | 2 ppm |
| Feb 3, 2014 07:58 | 2 ppm |
| Jan 25, 2014 08:30 | 4 ppm |
| Jan 4, 2014 09:18 | 2 ppm |
| Nov 25, 2013 07:47 | 2 ppm |