on thin ice vs precarious

on thin ice

prep
  • In a dangerous, hazardous, or delicate situation; at risk. 

adv
  • dangerously, hazardously, delicately 

precarious

adj
  • Dangerously insecure or unstable; perilous. 

  • Relating to incipient caries. 

  • Depending on the intention of another. 

How often have the words on thin ice and precarious occurred in a corpus of books? (source: Google Ngram Viewer )