studied vs time-served

studied

adj
  • Qualified by, or versed in, study; learned. 

  • Practiced; self-conscious; careful. 

time-served

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

  • Having completed many years of service. 

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