A new report from the Pew Research Center has revealed Brazil's changing religious landscape.
One of the biggest Catholic youth events, World Youth Day, is about to take place in Rio but Pew's analysis finds that the number of Catholics in the host country continues to fall.
Meanwhile, the number of Brazilians describing themselves as Protestant is rising, as is the proportion of the population identifying with other religions or no religion.
Brazil is still home to the largest Catholic population in the world, standing at an estimated 123 million people.
But between 1970 and 2000, the proportion of the population identifying as Catholic fell even though the number of Catholics actually grew.
From 2000 to 2010, however, both the absolute number of Catholics and the percentage of Catholics in Brazil declined, from 125 million - or 74% of the country's total population - to 123 million - or 65% of the population.
In the same decade, the number of Brazilians identifying as Protestant grew from 26 million (15% of the population) in 2000, to 42 million (22% of the population) in 2010.
Between 1970 and 2010, there has been a significant rise in the number of Brazilians affiliating with other religions, from around two million to 10 million - 5% of the population.
Brazilians with no religious affiliation have seen similar growth in numbers, from fewer than a million in 1970 to 15 million in 2010 - 8% of the population.
The decline in Catholics is evident across all age brackets, although the greatest fall has been in young Brazilians. Whereas 92% of Brazilians aged 15 to 29 in 1970 described themselves as Catholics, this fell by 29% to 63% in 2010. This was followed by the 30 to 49 age bracket, where Catholics fell from 91% in 1970 to 64% in 2010.
Conversely, Protestants have increased across all age brackets, most significantly among young Brazilians. While only 5% of 15 to 19-year-olds identified themselves as Protestant in 1970, this rose to 22% in 2010. These figures were mirrored in the 30 to 49 age bracket.