semi-professional vs semiprofessional

semi-professional

adj
  • playing for pay on a part-time basis 

  • composed of semi-professional players 

noun
  • a semi-professional sportsman or athlete 

semiprofessional

adj
  • Paid as a professional but on a part-time basis. 

  • Of or pertaining to a semiprofession. 

  • Of close to professional standard; prosumer. 

noun
  • A semiprofessional person. 

How often have the words semi-professional and semiprofessional occurred in a corpus of books? (source: Google Ngram Viewer )