| Group | Total valid answers | Answers corrected with LOCF | % |
| PG1 | 8148 | 101 | 1.2% |
| PG2 | 6406 | 95 | 1.5% |
| YG1 | 11,131 | 69 | 0.6% |
| YG2 | 7037 | 63 | 0.9% |