| Year | Euskera (%) | Spanish (%) | Bilingual (%) |
| 1991 | 10.0 | 84.5 | 5.5 |
| 2001 | 13.5 | 78.2 | 8.3 |
| 2006 | 12.5 | 81.4 | 6.1 |
| 2011 | 12.7 | 80.0 | 7.3 |
| 2016 | 13.4 | 79.5 | 7.1 |