petty theft vs thief

petty theft

noun
  • A theft of property having a value lower than a certain small amount set forth in a statute, and considered to be a less serious class of crime. 

thief

noun
  • One who steals another person's property, especially by stealth and without using force or violence. 

  • One who carries out a theft. 

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