In The God Delusion (at page 50), Richard Dawkins presented the following spectrum of theistic probability:

1. Strong theist. 100 per cent probability of God. In the words of C.G. Jung, 'I do not believe, I know.' 2. Very high probability but short of 100 per cent. De facto theist. 'I cannot know for certain, but I strongly believe in God and live my life on the assumption that he is there.' 3. Higher than 50 per cent but not very high. Technically agnostic but leaning towards theism. 'I am very uncertain, but I am inclined to believe in God.' 4. Exactly 50 per cent. Completely impartial agnostic. 'God's existence and non-existence are exactly equiprobable.' 5. Lower than 50 per cent but not very low. Technically agnostic but leaning towards atheism. 'I do not know whether God exists but I'm inclined to be sceptical.' 6. Very low probability, but short of zero. De facto atheist. 'I cannot know for certain but I think God is very improbable, and I live my life on the assumption that he is not there.' 7. Strong atheist. 'I know there is no God, with the same conviction as Jung "knows" there is one.' Incidentally, Dawkins placed himself at a “6″ on his 7-point scale. See also here.

This above scale is quite useful. How sure are you that there is no “God”? Now you can rank your own confidence level based on a scale that quantifies your beliefs; you can then compare your degree of beliefs to that of others. [More . . . ]