hinder vs pitch in

hinder

verb
  • To make difficult to accomplish; to act as an obstacle; to frustrate. 

  • To delay or impede; to keep back, to prevent. 

noun
  • The buttocks. 

adj
  • Of or belonging to that part or end which is in the rear or hind, or which follows. 

pitch in

verb
  • To help out; lend assistance; contribute; to do one's part to help. 

  • To begin briskly. 

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