Contrary to popular believe, the percent of cocoa in a chocolate is not always a measure of the quality. The true measure of quality is in the process used to produce the chocolate. The reason a brand like valrhona is so famed is because of the percentage of the actual cocoa butter used. The percentage of cocoa in a chocolate does not mean the cocoa butter content, it simply is a measure of the percentage of chocolate liquor (pure, unsweetened chocolate) used to produce it. Dark chocolates for this reason almost always have the highest numbers, and at the other end up the spectrum white chocolates will have the lowest number even though white chocolate is purely cocoa butter mixed with milk, sugar, and vanilla and put through the remainder of the chocolate production cycle. A great measure of quality of chocolate is the conching process. The reason many chocolates are more expensive when you see them (apart from the standard of quality used in the raw bean state) is because of the care given to this process, the reason being, the longer a chocolate is conched, the finer the texture will be on the tongue.