Is the number of people really all that relevant?
I mean, there are over a billion people in the world who identify as believers of Islam, many of whom report personal experiences which they consider overwhelming evidence that there is no God but Allah, and Mahomet is His Prophet. But I don't accept that there is no God but Allah. (And, I'm guessing, neither do you, so it seems likely that we agree that the beliefs of a billion people at least sometimes not sufficient evidence to compel confidence in an assertion.)
Going the other way, there was a time when only a million people reported personal evidence of Jesus Christ as Lord.
There was a time when only a hundred thousand people had.
There was a time when only a thousand people had.
Etc.
And yet, if Jesus Christ really is Lord, a rationalist wants to believe that even in 13 A.D., when very few people claim to. And if he is not, a rationalist wants to believe that even in 2013 A.D. when billions of people claim to.
I conclude that the number of people just isn't that relevant.
I think that if in 13 A.D. you had asked a rationalist whether some random Nazarene kid was our savior, "almost certainly not" would have been the correct response given the evidence. But twenty years later, after a whole lot of strong evidence came out, that rationalist would have adjusted his probabilities significantly. The number of people who were brought up in something doesn't matter, but given that there are millions if not billions of personal witnesses, I think God is a proposition to which we ought to give a fair chance.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.