How many people does it REALLY take to convict at a felony trial?

In the United States, a felony jury generally consists of 12 citizens selected at random with the aim of empaneling an impartial jury. In theory, all 12 jurors must arrive at a conclusion of guilty in order for the prosecutor to secure a conviction. However, juries deliberate once arguments are made, and one would be naive to think that this doesn’t have an effect on swaying the opinions of those in the jury minority. So how many people does a prosecutor really have to convince of guilt? 7? 8? 9? 10? Something else?

What percentage of certainty would you need to perceive something as proven beyond a reasonable doubt? 90%? 95%? Something else?