singer-songwriter vs songster

singer-songwriter

noun
  • A musician who both sings and composes, especially when recording or performing his/her own compositions. 

songster

noun
  • One who writes songs. 

  • A man who sings songs, especially as a profession; a male singer. 

  • A male songbird. 

  • A book of songs; songbook. 

How often have the words singer-songwriter and songster occurred in a corpus of books? (source: Google Ngram Viewer )