Reuters reports:

Islam has overtaken Roman Catholicism as the biggest single religious denomination in the world, the Vatican said on Sunday.

Monsignor Vittorio Formenti, who compiled the Vatican’s newly-released 2008 yearbook of statistics, said Muslims made up 19.2 percent of the world’s population and Catholics 17.4 percent.

He said that if all Christian groups were considered, including Orthodox churches, Anglicans and Protestants, then Christians made up 33 percent of the world’s population — or about 2 billion people.

The Vatican recently put the number of Catholics in the world at 1.13 billion people. It did not provide a figure for Muslims, generally estimated at around 1.3 billion.

Now wait a minute–is this stupidly obvious or am I just stupid?–but isn’t Catholicism a denomination of Christianity, while Islam is an entire religion, with denominations such as Sunni and Shi’ite? You can’t compare one branch of one religion against all branches of a different religion; that just doesn’t make sense.

But hearing any news about Islam expanding rapidly is enough to make a lot of people nervous; so why don’t you go ahead and vote in the following poll. And be honest. (I picked the third option.)