| Weighted class | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | Average 2010/15 |
| 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% |
| 20% | 1% | 1% | 1% | 1% | 1% | 1% | 1% |
| 35% | 3% | 2% | 3% | 3% | 4% | 4% | 3% |
| 50% | 3% | 4% | 4% | 4% | 3% | 3% | 3% |
| 75% | 8% | 13% | 12% | 9% | 6% | 5% | 9% |
| 100% | 30% | 25% | 25% | 27% | 30% | 38% | 29% |
| 150% | 4% | 5% | 5% | 5% | 7% | 5% | 5% |
| Total | 48.9% | 50.2% | 49.8% | 49.6% | 50.9% | 55.5% | 51% |