encomium vs pat on the back

encomium

noun
  • Warm praise, especially a formal expression of such praise; a tribute. 

  • The eighth exercise in the progymnasmata series. 

  • A method within rhetorical pedagogy. 

  • A general category of oratory. 

  • A genre of literature that included five elements: prologue, birth and upbringing, acts of the person's life, comparisons used to praise the subject, and an epilogue. 

pat on the back

noun
  • Praise, congratulations. 

verb
  • To praise or congratulate. 

How often have the words encomium and pat on the back occurred in a corpus of books? (source: Google Ngram Viewer )