This is clearly a blind spot of mine (as is Billy Joel).
Google ngrams, comparing usage of New Yorkers, Bostonians and Angelenos. The latter two are closer than I would have guessed. Went for the singular rather than plural to avoid the New Yorker magazine giving it an unfair advantage. New Yorkers is still far ahead but interesting how it's plummeted since 2004.
― Alba, Thursday, 15 October 2020 18:06 (three years ago) link