I would love to know the same, but I'm not sure # of votes is the biggest factor.

I am aware of some who made it to UC with 365 votes but others have made it with only 30 votes. One I had in UC some time ago had 171 votes.
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Based on number of comments you can extrapolate that some have made it to UC with 15 votes or less.
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I also have reason to believe that an idea I recently voted for and which won (was selected for development) had only 2-3 votes.