Languages of Catalonia
The main cause of Spanish and Catalan social bilingualism in modern Catalonia was large-scale migration from the rest of Spain during the 20th century, as Catalonia started a significant industrialization which demanded an increased workforce from elsewhere. Spanish has historically been spoken among a minority of civil servants born in other regions in Spain and among segments of the wealthiest bourgeoisie. Spanish has also been spoken as a second language by most Catalans, as it has been the only official language over long periods since the eighteenth century.
Catalonia
According to the linguistic census held by the Government of Catalonia in 2013, Spanish is the most spoken language in Catalonia (46.53% claim Spanish as "their own language"), followed by Catalan (37.26% claim Catalan as "their own language"). In everyday use, 11.95% of the population claim to use both languages equally, whereas 45.92% mainly use Spanish and 35.54% mainly use Catalan. There is a significant difference between the Barcelona metropolitan area (and, to a lesser extent, the Tarragona area), where Spanish is more spoken than Catalan, and the more rural Catalonia, where Catalan clearly prevails over Spanish.