guv'nor vs line manager

guv'nor

noun
  • An informal form of address to a man; see guv. This version is especially likely to be applied to the owner of a business or the landlord of a public house. 

line manager

noun
  • The manager who is directly responsible for an employee. 

How often have the words guv'nor and line manager occurred in a corpus of books? (source: Google Ngram Viewer )