I know that's what the Catalan government says, but is it actually the case? Wikipedia says

"As an official language, Spanish is understood almost universally in Barcelona. In addition, 95% of the population understand Catalonia's own native Catalan language, while 74.6% can speak it, 75% can read it, and 47.1% can write it"

A writing literacy of less than 50% sounds pretty poor.