Median Book Income!

Per the Authors Guild, their Author Income survey is "the most comprehensive study of its kind in the U.S. to date." For the 2023 survey, the Authors Guild surveyed: "Thirty-six other organizations, including Penguin Random House, Hachette Book Group, Ingram, B&N Press, PEN America, African American Literature Book Club [...] and 5,699 published authors."

Per the 2023 Author Income survey: "[...] the median book income (including advances, royalties, and fees from licensing and subsidiary rights) for full-time authors in 2022 was $10,000 [...]"

Therefore, per the Authors Guild, in 2023, 50% of full-time writers earned less than $10,000, while 50% earned more than $10,000. 

I won't share on what side of the median I fall on, but I do suspect that "full-time" is hyperbolic, because I suspect that, unlike Harry Lesser, most writers can't write full-time on a $10,000 income - especially if they live in The Big Apple.