The Chronicle of Higher Education liberal arts degrees generally:

Beckie Supiano, "How Liberal Arts Majors Fare over the Long Haul," Report of the American Association of Colleges and Universities, Chronicle of Higher Education, January 2014.

US News on undergraduate philosophy degrees:

Melanie Pincus, "What You Need to Know about Becoming a Philosophy Major," US News Education, 5 May 2020.

Illana Kowarski, "What You Can Do with a Philosophy Degree," US News Education, August 13, 2020.

ABC News on the earnings of philosophy B.A.s:

Farai Chideya, "Philosophers Don't Get Much Respect, But Their Earnings Don't Suck," fivethirtyeight.com, ABC News, 11 November 2015.

Wall Street Journal data on relatively high earnings of philosophy B.A.s:

"Salary Increase by Major," data from PayScale.com