Doc Martens vs half-boot

Doc Martens

noun
  • Dr. Martens-brand footwear, especially a style of high lace-up leather boot with air-cushioned sole, traditionally associated with British skinheads, adopted by other subcultures at various times. 

half-boot

noun
  • A boot with a short top covering only the ankle. 

How often have the words Doc Martens and half-boot occurred in a corpus of books? (source: Google Ngram Viewer )