I checked the ratings from last year. There is a median being calculated, something like average number of ratings but with weird stochatisc math. Last year it was 8 rates in median. This year it might be a bit more.
But in the top 100 were games with only eight to ten votes. All of them were 5 stars though. But so the total amount doesn't really matter. I think the amount of ratings just have to be higher than this median.
In other words 10 five star votings might be better than 30 - 50 votes with an average of 3.5.
Correct me of I'm wrong.