The Probability of God Existing

Can we meaningfully ascribe probabilities to credence of beliefs in this way? I mean, what really is the difference between being 60% sure that God exists and 62% sure? Dawkins does that in the God delusion. We want to hold hypotheses as provisionally true. Belief is in binary. So I'm far more certain that the world existed before I was born. That's like one of my chief beliefs. If I were assigning probabilities to things in my life, that would be 100.