adequate vs third string

adequate

det
  • A sufficient amount of; enough. 

adj
  • Equal to or fulfilling some requirement. 

third string

adj
  • Of a decidedly lower quality or condition. 

noun
  • A unit of players that plays behind the first and second strings; a junior varsity team. 

How often have the words adequate and third string occurred in a corpus of books? (source: Google Ngram Viewer )