|
Month
|
2011
|
2010
|
2009
|
| January | 1.56 | 1.49 | |
| February | 1.56 | 1.49 | |
| March | 1.48 | 1.46 | |
| April | 1.48 | 1.50 | |
| May | 1.48 | 1.45 | |
| June | 1.25 | 1.45 | |
| July | 1.45 | ||
| August | 1.35 | 1.45 | |
| September | 1.45 | ||
| October | 1.45 | ||
| November | 1.25 | 1.50 | |
| December | 1.25 | 1.50 |