According to C.E. Hooper, Inc. on November 2nd, 1948–Election Night–74.1% of television households in New York City were watching election coverage between 9PM and 11PM on one of five stations.
Here are the specifics:
Before reporting Hooper’s ratings for radio and television, The New York Times noted, “Should anyone still believe in polls,” a reference to the now infamous upset that saw incumbent Harry S. Truman defeat heavily favored Thomas E. Dewey.
1 “Radio and Television.” New York Times. 4 Nov. 1948: 58.