potency vs skill set

potency

noun
  • The ability or capacity to perform something 

  • Concentration; strength 

  • Sexual virility: the ability to become erect or achieve orgasm. 

  • Potentiality, ability, capacity. 

  • Power, authority. 

skill set

noun
  • The skills needed to accomplish a specified task or perform a given function. 

  • A set of skills. 

How often have the words potency and skill set occurred in a corpus of books? (source: Google Ngram Viewer )