In response to the OP:
Percentages prove nothing. It is a case by case situation, and each case needs to be evaluated separately.
Before determining whether or not a child should be allowed to pursue various unpleasant behaviors or activities in the home, the parents should try to understand what the child is going through, where this is coming from, and what the future ramifications are. Sometimes, it is better to seek guidance from a counselor or Rav who knows the family well, who can provide their unbiased opinion on the healthiness of the parents’ relationship with their child, and together, they can determine how to proceed. This should never be decided based on findings related to other cases, because every child is different and has different experiences, reactions, associations and feelings.
To kick a child out, or keep a child in, simply because of a percentage, or because of a statement from a Rav regarding some other, unrelated case, is irresponsible and potentially deadly.