| Weighted class | 2010 | 2011 | 2012 | 2013 | 2014 | 2015 | Average 2010/15 |
| 0% | 23% | 22% | 28% | 23% | 22% | 20% | 23% |
| 20% | 2% | 1% | 3% | 2% | 4% | 1% | 2% |
| 35% | 13% | 14% | 13% | 13% | 12% | 12% | 13% |
| 50% | 6% | 10% | 11% | 13% | 7% | 6% | 9% |
| 75% | 14% | 11% | 8% | 8% | 10% | 9% | 10% |
| 100% | 40% | 39% | 34% | 38% | 38% | 48% | 40% |
| 150% | 4% | 4% | 4% | 4% | 6% | 4% | 4% |
| Total | 100% | 100% | 100% | 100% | 100% | 100% | 100% |