| January |
| February |
| March |
| April |
| May |
| June |
| July |
| August |
| September |
| October |
| November |
| December |
|
| 51.94 |
| 48.49 |
| 49.92 |
| 73.68 |
| 57.23 |
| 63.82 |
| 61.59 |
| 56.95 |
| 54.47 |
| 67.27 |
| 65.33 |
| 63.01 |
|
| 70.91 |
| 60.77 |
| 57.72 |
| 56.15 |
| 65.16 |
| 64.81 |
| 53.96 |
| 65.36 |
| 69.23 |
| 65.81 |
| 70.20 |
| . |
|
| 18.97 |
| 12.28 |
| 7.8 |
| -17.53 |
| 7.93 |
| 0.99 |
| -7.63 |
| 8.41 |
| 14.76 |
| -1.46 |
| 4.87 |
| . |
|
| January pass rate rises significantly |
| February pass rate rises significantly |
| March pass rate rises |
| April pass rate falls significantly |
| May pass rate rises |
| . |
| July pass rate falls |
| August pass rate rises |
| September pass rate rises significantly |
| . |
| . |
| . |
|