From what I have read, about 5,000-9,000 blacks served in the Continental Army and Navy. About 20,000 blacks served in the British Army and Royal Navy.
A significant number to be sure. But you can’t divide that number by the peak strength of the Continental Army and then claim that that percentage is relevant. You’d have to divide by the total number of Continental Army veterans — and I don’t think anybody knows that number with any accuracy. (I’m sure I’m not telling you anything you wouldn’t already know)