Folks can get burs under their saddles pretty quick around here. "Britons" can refer to persons who live in Great Britain or it can refer to the Celtic peoples of the British Isles (a.k.a. Brythons
). From the context, it's clear you meant the first definition. Be assured that some of us actually understood that.
As for your question, though, I don't know if anyone can answer. Statistics for that era are, of course, unavailable. Furthermore, there was a good deal of intermingling between the pre-conquest Anglo-Saxons and the Normans, so that, by the fourteenth century, we're really dealing with an Anglo-Norman population. And even if the Anglo-Saxons didn't have Norman blood, they were becoming culturally Anglo-Norman. The notion that there was a sharp delineation between the ruling Normans and the subjugated Saxons is the stuff of literature -- Robin Hood
especially. The historical record is rather more nuanced.