aside from vs if not

aside from

prep

  • in addition to 

  • excluding; with the exception of 

if not

adv

  • Used to link a semantically weaker word to a semantically stronger word following the adverb, both sharing the same basic meaning, indicating the increased likelihood of the former. 

How often have the words aside from and if not occurred in a corpus of books? (source: Google Ngram Viewer )