fun size vs imperceptible

fun size

adj
  • Small in size. 

noun
  • A small size. 

imperceptible

adj
  • not perceptible, not detectable, too small in magnitude to be observed 

  • beyond the purview of man; too great and all-encompassing to be perceived. 

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