One time I took a job at the offered salary. I was contacted by another company I had done some part time work for and they offered me a full time job at a considerably higher salary. I told my current boss and he said there was a company policy of max 15% increase in any year, but he gave me the 15%. I think the point is that you need to give your boss some numbers based on current rates at other companies. You don't have to give the company names unless he presses you very hard.