I've heard about William the Conqueror's invasion bringing the then-current French language to Britain, but what about the fact that the Romans occupied Britain? In other words, what percent of the Latin in English came from the occupation of Rome, and what percent came from the Norman conquest?

I've heard about William the Conqueror's invasion bringing the then-current French language to Britain, but what about the fact that the Romans occupied Britain? In other words, what percent of the Latin in English came from the occupation of Rome, and what percent came from the Norman conquest?