At Agincourt (1415) the English reportedly had 1,500 men-at-arms (aka: Knights) and 7,000 longbowmen. That would be a ratio of nearly 5 longbowmen per knight.
The French side has a lot of conflicting estimates of size, but by all accounts was very heavily weighted toward men-at-arms. Estimates generally run north of 10,000, with only about 5,000 archers and crossbow. That would give us a ratio of somewhere between 1 or 2 knights per archer/bowman. (At least one other source numbers the total French army at 50,000 with the rearguard added in, but said that they wouldn't let the archers participate, for fear of friendly fire).
Of course this battle is rather famous as an example of how immense numbers of knights could be slaughtered by longbowmen if conditions are right. The French of this period were rather enamored of impulsive ill-advised mounted charges (see also Crecy, Poitiers, Nicopolis), while English knew how to use that against them, often chosing a very good defensive position with large numbers of men-at-arms fighting unmounted.