time-served vs trained

time-served

adj
  • Having completed an apprenticeship or period of training, thus acquiring skills. 

  • Having completed many years of service. 

trained

adj
  • Having undergone a course of training (sometimes in combination). 

  • Manipulated in shape or habit. 

How often have the words time-served and trained occurred in a corpus of books? (source: Google Ngram Viewer )