Protestant Catholic Jewish
Harvard 7.6% Notre Dame 24.3% Harvard 18.2%
Yale 6.2% Harvard 7.9% Chicago 7.8%
USMA 2.6% Yale 3.5% Columbia 6.5%
Michigan 2.5% MIT 3.5% NYU 6.5%
Illinois 2.4% USMA 3.2% Cornell 3.9%
MIT 2.4% Michigan 2.6% Notre Dame 3.9%
Columbia 2.0% Berkeley 2.3% CCNY 3.9%
Minnesota 1.9% Fordham 2.3%
Berkeley 1.8% Columbia 1.8%
Ohio State 1.8% Cornell 1.8%
The general pattern was what I expected, but I wasn't ready for the degree to which Notre Dame led among Catholics. Among Protestants, the top choice (Harvard) had less than the combined totals of #2 and #3; among Catholics, Notre Dame had more than the combined totals of the next six.
The University of Chicago was the second choice among Jewish parents, and was just off the top ten among Protestants, but was chosen by only one Catholic parent. I don't know enough about the history of that university to offer an explanation.
Notre Dame was tied for fifth choice among Jewish parents, and was among the top 15 among Protestants. That could have been because of academic reputation, but football may also have been a factor. Notre Dame had been national champions (according to the AP poll) in 1943, 1946, 1947, and 1949. Most of the people answering the survey had not attended college themselves, and probably didn't have much information to base a response on, so some may have said Notre Dame simply because it was a name that they knew. However, even if Notre Dame's standing was boosted by football, Catholic parents clearly had a strong inclination to favor Catholic colleges (Fordham was also in the top 10, and Boston College just missed).