snail's pace vs trudge

snail's pace

noun
  • A very slow pace. 

trudge

noun
  • A tramp, i.e. a long and tiring walk. 

verb
  • To walk wearily with heavy, slow steps. 

  • To trudge along or over a route etc. 

How often have the words snail's pace and trudge occurred in a corpus of books? (source: Google Ngram Viewer )