Postflop Minraises at $200 and $400

[banditbdl]

I did a search but didn't really find the kind of info I was looking for.

When somebody you don't know much about (i.e. average mediocre player) minraises you postflop in these games what percentage of the times do they have a monster? I was just getting back into the swing of playing today and saw a lot of minraising and it got me to thinking. Is this the big time goods 70% of the time, 80%, 90%, even higher? How often are people making a move with this? How often do they even know what the goods really are?