point of contention vs wrangling

point of contention

noun
  • A matter that forms the basis of a disagreement, struggle, etc. 

wrangling

noun
  • a dispute; a contentious argument; a brawl 

  • dispute; disputation; quarreling 

  • contention; gainstriving 

How often have the words point of contention and wrangling occurred in a corpus of books? (source: Google Ngram Viewer )