The only question I have is what is the Vatican's pressing interest in Islam. Why does the pope and the Vatican always side with Arafat types and Muslim Nazis. In any event, the recent reports were mistaken, very mistaken. I would go so far as to call them DISHONEST.
Islam consists of Sunni and Shia. The Sunni do not consider Shia to be Muslims! Often this is even used as a pretext for Muslim-on-'Muslim' genocides. See Iran-Iraq war for one example. Each views the other side as an illegitimate cult and "not true Islam." So why does the Vatican count them all as one faith - Islam? According to Saudi estimates (which are probably dishonest and likely to portray Shia as less than they are in reality), Shia comprise 15% of the world's Muslims!!! So if you subtract the Shia, Sunnis are not even as many as there are Catholics. Furthermore, why if we are counting Shia and Sunni together under the branch of "Islam" (even if they don't do that themselves), why then is "Catholicism" considered one sole faith? Would not ALL Christians need to be counted together if we're counting ALL Muslims, sunni and shia together?
Thus, if we use the same criteria applied to both sides, the largest faith in the world is "Christianity" (all Catholics plus all other Christians) while the second-largest is "Islam" (All Sunnis plus all Shia). So even in this criteria Islam is not the world's largest religion.
Death to Islam.