| N˚-1 | Sample 1 | N˚-2 | Sample 2 | N˚-3 | Sample 3 |
| a | 2443 | a | 2444 | a | 2432 |
| b | 1043 | b | 720 | b | 1052 |
| % | 58 | % | 59 | % | 55 |