| Operation approach | Mean | Dev. std. | Median | Minimum | Maximum |
| Open | 12.56 | 5.32 | 10.00 | 8.00 | 32.00 |
| VL | 9.90 | 3.20 | 9.00 | 7.00 | 19.00 |
| VL converted | 11.68 | 3.60 | 10.00 | 8.00 | 19.00 |