there's not really an *average* amount--it varies person to person. there are some who theorize there is an addictive quality to the behavior.

you should probably see a therapist about this (if you're not already seeing one). personally, i think cutting is a coping mechanism so there are reasons you want to do this--your therapist should be able to help you figure out what they are.

it's often difficult to stop this, so don't get discouraged if you try and it doesn't happen quickly.