| Month | Change |
|---|---|
| 5/10 | -2.10 |
| 6/10 | -2.21 |
| 7/10 | -2.30 |
| 9/10 | -2.22 |
| 10/10 | -2.17 |
| Month | Change | 4/11 | -1.90 |
| 5/11 | -1.21 |
| 7/11 | -1.81 |
| 8/11 | -2.00 |
| Month | Change | 7/12 | -2.19 |
| 8/12 | -2.30 |
| 9/12 | -2.47 |
| 10/12 | -2.43 |
| Month | Change | 4/13 | -2.44 |
| 5/13 | -2.27 |
| 6/13 | -2.22 |
| 7/13 | -2.10 |
| 8/13 | -2.14 |
| 9/13 | -2.13 |
| Month | Change | 3/14 | -2.06 |
| 4/14 | -2.07 |
| 5/14 | -2.03 |
| 6/14 | -2.14 |
| 7/14 | -2.30 |
| 8/14 | -2.41 |
| 9/14 | -2.59 |
| 10/14 | -2.68 |
| Month | Change | 4/15 | -2.76 |
| 5/15 | -2.61 |
| 6/15 | -2.50 |
| 7/15 | -2.33 |