Task: Question Decomposition
Input (English): question: Find the number of universities that have over a 20000 enrollment size for each affiliation type.
Output (English): #1 return affiliation types 
#2 return universities of #1 
#3 return enrollment sizes of #2 
#4 return #2 where #3 is  higher than 20000 
#5 return number of  #4 for each #1