Table 1: Territorial distribution of sample units.
| Territorial area | n. | % |
| North-West | 625 | 25.0 |
| Torino | 300 | 12.0 |
| Milano | 325 | 13.0 |
| North-East | 450 | 18.0 |
| Bologna | 225 | 9.0 |
| Padova | 225 | 9.0 |
| Centre | 600 | 24.0 |
| Firenze | 250 | 10.0 |
| Roma | 350 | 14.0 |
| South-Islands | 825 | 33.0 |
| Bari | 275 | 11.0 |
| Napoli | 275 | 11.0 |
| Palermo | 275 | 11.0 |
| Total | 2500 | 100.0 |