How important were the 13 American colonies to the British economy in the mid 18th century? How big a loss was American independence to the Empire and Crown's ledgers?

by Kumquats_indeed

Do we know about what percentage of the British Empire's colonial revenue came from the 13 Colonies in the years before the American Revolution? I imagine that the sugar producing Caribbean colonies and the trade out of India were bigger cash cows. And how directly invested was King George in the American colonies? Did their loss hurt his personal finances in particular?

Also, how significant were the expenses of waging the war against the rebelling Americans? Were they hemorrhaging cash to keep the war going, merely an irritating nuisance, or somewhere in between? Was it necessary for the British to borrow any significant sums of money to keep the war going?

Any other information about the economics of the British side of the war would also be appreciated, thank you.

Holy_Shit_HeckHounds

Here is a previous answer to a similar question by u/ReaperReader from about a year ago. Hopefully it can hold you over until someone else contributes some more specifics you are looking for