ABC News' Dan Kloeffler reports:
Every year, the Vatican publishes a Statistical Yearbook, after compiling information on the number of Catholics around the world. The latest report was released in 2012 and showed the number of followers had increased to nearly 1.2 billion people.
According to world census figures used by the Vatican, Catholics were 17.5 percent of the world population at the end of 2012.
Since the very first pontiff, Saint Peter, was installed as head of the Catholic church in 32 A.D., 264 men have been elected to the papacy by the College of Cardinals.
The longest-serving was Blessed Pius IX, for 32 years starting in 1846. John Paul I had the shortest of all papacies. He died in October 1978, only 33 days after his election.
Of the 207 members in the College of Cardinals, 115 are under the age of 80 and are therefore eligible to vote for the next Pontiff.