I think that if you have to look at a list to see how you stack up, your not making enough. Unless you just want to see how far ahead you are....
Employers probably put these lists together to keep the work force from getting the $$.
I've never been turned down for a raise that I requested. However, I don't get greedy. Just want motivation to get out of bed and drive 25 miles to sit on my butt all day staring at a computer screen. Need more motivation every year.