Pay ranges for skill sets varies by geographic area and time. What is highly paid today may not be so highly paid two years ago, or two years from now. A local shortage of a skill set may cause rates to go up in an area. A big IT employer laying off staff could depress rates in an area for a period of time. There is no universal statement possible about skills sets that are highest paid since there's just too much variability.
Google "salary surveys" and do your own research, remembering that what you find today will change -- possibly quite rapidly -- as local conditions and time changes.