The caniuse.com data on http&#x2F;2 appears to have some flaws.
Biggest buckets for browsers that support SPDY but not HTTP&#x2F;2 for our website right now are:
a) Chrome for mobile
b) Safari on older Mac OS X versions 
c) Older Chrome for desktop versions 
d) Internet Explorer (small impact)
Other websites might see different ratios depending on their audience.<p>Stay tuned for instructions on how to gain protocol version insight for your own website on CF.