That didn't answer my question at all. You said "if you want to get a 15% or more raise, you need to jump somewhere else". That's just coming out of thin air or

That didn't answer my question at all. You said "if you want to get a 15% or more raise, you need to jump somewhere else". That's just coming out of thin air or based on "other companies do it". If you do work in HR or as a manager, what's the rational basis deciding just that number?