Before Yorktown, how many battles had the Continental Army fought and
how many had it lost?

I have read that it had lost 19 out of 21 battles. But I cant remember
the reference giving those numbers.

Please supply a reference to a relevant published report/book/on-line
website with your answer.

And please, be objective about what is a victory/defeat. And please,
no American apologists eager to assert that the American
Army was perfect.