FOI: Why Won’t the Department of Education Reveal How Many Parents Chose Multidenominational Schools?

Why does the Department of Education believe it’s too sensitive to share how many parents chose multidenominational education?
I sent a Freedom of Information request to find out the total percentage of parents that voted for multidenominational schools
https://simonmlewis.substack.com/p/why-does-the-department-of-education