W3Schools' statistics may not be relevant to your web site. Different sites attract different audiences. Some web sites attract developers using professional hardware, while other sites attract hobbyists using older computers. Anyway, data collected from W3Schools' log-files over many years clearly shows the long term trends.
Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
