The Philosophical Gourmet Report has some useful data.
https://philosophicalgourmet.com/report-2022/undergraduate-study-2/
Also, when I was looking at this a year or so ago, I found a source that discussed undergrad options, but I can't find the link. It analyzed admissions to the elite U.S. phD programs and came up with a list of colleges that are successful in getting the students into them. "Elite" was defined by the author as top 25 “national research universities” or the top 15 “national liberal arts colleges,” plus NYU, Rutgers, Michigan, Pitt, and Reed due to the the top-five PGR ranking of their philosophy PhD programs.
All I have are my notes on it (apologies to source):
"Of the 183 students with listed U.S. undergraduate degrees, 106 (60%) hailed from the elite schools defined above.
Five universities contributed at least eight students to the list, that is, at least one student per examined PhD program: Berkeley (10), Chicago (10), NYU (10), Harvard (8), and Stanford (8). These five schools alone are responsible for 25% of listed students.
Several other elite schools contributed at least four students each: Rutgers (6), Princeton (5), Yale (5), Dartmouth (4), Reed (4), and Williams (4).
Each of the top ten ranked national universities contributed at least one student.
The full list of elite programs is: Amherst College (2), Berkeley (10) Brown (3), Carleton College (3), Chicago (10), Claremont McKenna, Columbia (3), Cornell, Dartmouth (4), Emory, Grinnell (2), Harvard (8), Haverford (2), Johns Hopkins (2), MIT, Northwestern (2), NYU (10), Penn (3), Pitt, Pomona, Princeton (5), Reed (4), Rutgers (6), Stanford (8), USC, Virginia, Washington U. St Louis, Wellesley, Williams (4), and Yale (5).
The full list of nationally ranked but nonelite schools is: Alabama, Arizona State (2), Auburn, Biola (2), Boston College, Brandeis (2), Cinncinnati, Franklin & Marshall, Furman, Houston, Illinois College, Indiana (2), Kenyon, Lafayette, Lewis & Clark, Marquette, Maryland-Baltimore County, Minnesota (2), Missouri-Columbia, North Carolina State, Northeastern (2), Oberlin (2), Pepperdine, Purdue, Sewanee, St Johns, SUNY Binghamton, SUNY Stony Brook (2), UC Davis, UC San Diego (2), University of Missouri-St Louis, UNC Chapel Hill (5), UNC-Asheville, Union College, University at Buffalo-SUNY, Vermont, Wake Forest, Washington-Seattle, West Point, West Virginia, Westmont, Wheaton, Whitman, and William & Mary.
The top ten most awarded undergrad degrees in philosophy are Penn, UCLA, UC Santa Barbara (693), Boston College (654), UC Berkeley (644), Washington-Seattle (485), Wisconsin-Madison (478), UC Santa Cruz (468), Colorado-Boulder (428), and University of Arizona (426).