The majority of the Spanish population is Catholic (about 67%), although many of these people do not practice Catholicism regularly, and only about 14% do.
About 21% are not religious, and it appears to be an increasing percentage.
The religion that is increasing and growing the fastest in Spain is Islamic. This is because of the growing amount of immigrants in Spain. Islamic people practice their religion more than Catholic people practice theirs.
Judaism, Protestantism and Hinduism, Orthodoxy, and more.