Sorry, I’m a little late to this party. Been busy lately. Caught a bit of a break tonight. Anyway, to answer your question…
For starters, are you looking for complete and exact, or would an overall general percentage suffice? I ask only because to get the answer you THINK you want, you will have to track down every atheist in existence and ask each individual atheist that question so that you can categorize each answer into its relevant group. (Just so you know, it might take a little while to do that.) Then you could (possibly) count the answers in each category and determine the percentage of each answer. To put it another way, you might as well have asked, “What is the favorite ice cream flavor of atheists?”
It would seem you have zero understanding of what atheism is. Not that it was really necessary for me to point that out. But, hey, they don’t call me “Captain Obvious” for nothing… (shrugging shoulders)…