http://caniuse.com/#compare=firefox+21,chrome+27 http://caniuse.com/#compare=firefox+21,chrome+27 I'm not sure how they're calculating 87% -- do unknowns count

http://caniuse.com/#compare=firefox+21,chrome+27 http://caniuse.com/#compare=firefox+21,chrome+27 I'm not sure how they're calculating 87% -- do unknowns count towards supported? It looks like, from that list, that Chrome supports more.