bad apple vs malevolent

bad apple

noun
  • A person who is not wholesome, honest, or trustworthy, especially one who has an adverse influence on others. 

malevolent

adj
  • Having an evil or harmful influence. 

  • Having or displaying ill will; wishing harm on others. 

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