What makes you say "majority"?

Let me make up a number. 7%. I think that number of plea bargains would be a huge problem if in 7% of cases the person is in fact innocent. Would you disagree?

And even generally assuming guilt, a number that high gets worrying. Maybe we're only prosecuting the strongest of strong cases or something, but some of the other factors that could be reducing the rate of trials are really bad for justice.