It varies program to program and year by year. If you want to see some school statistics, you can buy a 3-month subscription to APA's book on these programs: https://gradstudy.apa.org/ for $20. This contains each school's data from 2018-2019 year. This does not have information on waitlists, but it does say x people were offered admission and y people enrolled. It also tells you about what parts of the application the program gives weight too. I like having it and its nice to refer to but its more useful before you apply. If you have a specific school or two, message me and I can send you the stats.