never vs until hell freezes over

never

adv
  • Negative particle (used to negate verbs in the simple past tense; also used absolutely). 

  • At no time; on no occasion; in no circumstance. 

  • Not at any other time; not on any other occasion; not previously. 

intj
  • A statement of defiance 

until hell freezes over

prep
  • forever; without success, no matter how long one perseveres 

How often have the words never and until hell freezes over occurred in a corpus of books? (source: Google Ngram Viewer )