| Date | Value |
|---|---|
| 2011-08-17 | 3.70 |
| 2011-08-16 | 3.82 |
| 2011-08-11 | 3.83 |
| 2011-08-01 | 3.89 |
| 2011-07-04 | 3.73 |
| 2011-06-25 | 3.68 |
| 2011-06-21 | 3.82 |
| 2011-06-13 | 3.85 |
| 2011-05-31 | 3.96 |
| 2011-05-24 | 3.57 |
| 2011-05-06 | 3.61 |
| 2011-03-30 | 3.65 |
| 2011-03-07 | 3.41 |
| 2011-03-04 | 2.67 |
| 2011-01-19 | 1.72 |