Arbitron made its first survey of New York City in May 1965, here's how the FMs fared in that survey... yes, 10.4 shares for FM (the top 3 stations that survey, WABC, WOR and WMCA, each had a larger share than the FMs combined.)
12. WPAT-FM 1.8
13. WTFM 1.7
14t. WQXR-FM 1.5
14t. WPIX-FM 1.5
17. WNEW-FM 0.8
18t. WVNJ-FM 0.7
18t. WRFM 0.7
20t. WNYC-FM 0.4
20t. WOR-FM 0.4
20t. WCBS-FM 0.4
23. WABC-FM 0.3
24t. WNBC-FM 0.2
WPAT, WQXR, WNEW, WVNJ, WNYC, WOR, WCBS, WABC and WNBC were all simulcasts of their more popular AM sister stations, so the fair comparison is to add the AM's and the FM's together to get each station's combined listenership.
Among the standalone FMs, WTFM surprises me. Back then it was either still transmitting from Queens (their tower could be seen from the Long Island Expressway near Utopia Pkwy, where the studios also were), or had recently moved to the Chrysler Building with a directional antenna to the east, so their signal was inferior west of the Hudson. And yet, 'TFM garnered a 1.7 as a semi-competitive standalone. (I know it was
the FM station that played in my house, hour after hour, anytime my mom fired up the big, "But it's beautiful furniture! 🤣 " console radio in our living room.) That tells me they must have had a disproportionately high share of Queens, Brooklyn, the Bronx and Nassau County.
WRFM was also a standalone, also playing beautiful music. Maybe they were still owned by Sonderling and were still transmitting from Woodside, Queens in those days. If they had already made the move to Empire, I'd have expected them to be doing much better.
WOR in those days was all-talk (except on weekends and a few records an hour during the Rambling with Gambling AM Drive show), so there was little benefit to listening to their FM simulcast, since their 710 AM signal was so strong, clean and dominant back then. WNBC was also largely talk, so ditto. But the other simulcasts were BM or classical, or in WCBS's case, a "Dead in the Middle of the Road" format which might have benefited a little bit -- like 0.4 share points -- from being on FM. But after the FCC issued its non-duplication edict in '65, and WOR-FM launched in the summer of '66, FM in NYC was literally off to the races.