bombproof vs childproof

bombproof

verb
  • To make resistant to bomb blasts. 

noun
  • An air-raid shelter, a structure designed to give protection against air raids and bombs. 

adj
  • Sufficiently strong to resist the effects of a blast from a bomb. 

childproof

verb
  • To make something childproof. 

adj
  • Designed to be unable for a child to use, operate, or open. 

  • Made safe from children; resistant to damage by children. 

  • Made safe for children. 

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