| Shape of the 1st MT head | R | L | ||
| N | % | N | % | |
| Rounded | 6 | 37.5 | 10 | 50.0 |
| Intermediate | 2 | 12.5 | 4 | 20.0 |
| Marginal | 8 | 50.0 | 6 | 30.0 |
| Total | 16 | 100.0 | 20 | 100.0 |