pillowcase vs ticking

pillowcase

noun
  • A washable, easily removable cloth cover for pillows. 

ticking

noun
  • A strong cotton or linen fabric used to cover pillows and mattresses. 

  • A sound of something ticking. 

  • A marking that occurs on some horses. It involves white flecks of hair at the flank, and white hairs at the base of the tail, called a skunk tail or rabicano. Sometimes referred to as birdcatcher ticks. 

  • An illusional style of dance where one moves his or her body to the "tic" of the music creating a strobe or animated effect. 

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