anticlockwise vs counterclockwise

anticlockwise

adj
  • in a circular fashion so as to be moving to the left at the top of the circle and to the right at the bottom (when viewed from the front), in the opposite direction to the way the hands of an analogue clock move. 

adv
  • In an anticlockwise fashion. 

counterclockwise

adj
  • Moving or located in the direction of rotation opposite from clockwise. 

adv
  • In the direction of rotation opposite from clockwise. 

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