tip over vs topple over

tip over

verb
  • (to cause) to topple over and fall 

noun
  • An action where the goalkeeper deflects the ball over the crossbar. 

topple over

verb
  • To fall over (to fall from an upright or standing position to a horizontal or prone position). 

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