This is going to be an unpopular observation, but most people that are charged are guilty. This is actually why the presumption of innocence is so important! If most people charged were actually innocent then there would be no need to explicitly presume innocence. Prosecutors generally don't bring a case to court unless there is sufficient evidence.
Just a point to consider: this is dependent on what you mean by "are guilty". The incentive to encourage plea deals by courts, prosecutors and attorneys, along with a perceived leniency of outcomes among many in law enforcement has contributed to the practice of over charging. This is especially true for certain categories of crime, drug charges being one of those categories. So while I would agree that most people charged are guilty on some of the charges, I posit that most people charged may not be guilty of all charges initially levied against them.
You might well be right but by what basis do you establish this? The percentage that is convicted? This would ignore any bias in the system whatsoever. The presumption of competence? The FBI admitted after decades of relying on hair analysis that it spent decades just lying and actually couldn't tell human hair from dog hair.
