73.3% of Spaniards claim to be Catholic, although 57.1% say they "hardly ever" go to mass.
According to data released today by the Centre for Sociological Investigations (CIS), the number of Spaniards claiming to be Catholics has dropped by 2% compared with the 2010 figures, when 75% of those surveyed claimed to be Catholic, and confirms the tendency seen over the past decade.
The CIS survey shows that only 2.2% of the population in Spain practise other religions.
14.9% of those surveyed said they were "non believers", a percentage which is increasing as steadily as the number of Catholics drops. In addition to the "non believers" 7.4% of Spaniards claimed to be "atheist".
The CIS also asked members of the public how often they went to church, excluding so-called social occasions like weddings, Christenings, First Holy Communions or funerals.
The majority (57.1%) said they "hardly ever" went - this figure was 47% in 2005 and was bearly over 40% a decade ago.
Just 15.9% say they attend a religious service most Sundays ad feast days, a figure which has also been falling gradually over the past ten years.