dreadlocks vs hairdressing

dreadlocks

noun
  • A hairstyle worn by Rastafarians and others in which the hair is left to grow into long matted strings. 

hairdressing

noun
  • The washing, colouring, cutting and styling of the hair; the art or trade of a hairdresser. 

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