According to research by the Pew Research Institute a significant proportion of Spaniards who grew up as Catholics have lost their faith in adulthood. The drop in adherents in Spain is one of the most pronounced in Western Europe. Only Belgium and Norway have seen a greater drop.
Of the respondents to their survey undertaken between April and August 2017, 92% stated thay had been raised Christinan (which in post-Inquisition Spain means Catholic) but only 66% remained Christian in adulthood as the graph below shows.
Of the 66% who consider themselves still to be Christian only 21% attend church at least once a month, slightly more than the U.K. but less than Austria, Germany or Switzerland.
Finally, the propertion of respondents who state that they are atheists, agnostics or have no religion is higher in Spain than all Western European countries surveyed apart from the Benelux countries and the Scandinavian countries of Norway and Sweden.
This research depicts a country that perhaps few people outside of Spain would recognise. It is certainly one of the most tolerant and socially liberal Western societies with a less negative opinion of muslims and with gay marriage and same sex-adopition legalised since 2005.