VATICAN CITY - Islam has "overtaken" Catholicism in number of adherents, though Christianity as a whole remains the world's most widely professed faith, the Vatican's top statistician said.
"For the first time in history we are no longer at the summit: The Muslims have overtaken us," said Monsignor Vittorio Formenti, head of the Central Office of Church Statistics, in the March 30 edition of the Vatican newspaper L'Osservatore Romano.
Muslims accounted for 19.2 percent of the world's population in 2006, whereas Catholics made up 17.4 percent, Formenti said, giving the total number of Catholics as 1.13 billion.
All Christian denominations together accounted for 33 percent of the world population, the Vatican official noted.
Formenti suggested that the head count of Catholics was more "scientific" than the Muslim figures. The Vatican collects its data through surveys by Catholic dioceses and parishes, he explained; whereas the number of Muslims is based on information provided by Islamic states, which rely primarily on estimates of population growth.
"While Islamic families continue to beget many children, Christians instead tend to have ever fewer," he said.
Formenti also noted statistical trends within the church, including a rise in the number of men studying for the priesthood.
"It's the first time that the trend is positive at such levels," he said, noting that there were 115,000 men enrolled in seminaries around the world, compared to only 79,000 three decades earlier.
The region of fastest growth for priests is Asia, above all the Philippines, he said, while the least fertile terrain is found in three European countries: France, Belgium and the Netherlands.