armband vs armfloat

armband

noun
  • An inflatable band worn round the arms to keep afloat in water 

  • A band worn around the arm of the captain of a team. 

  • A band worn around the arm, usually to symbolize protest or mourning. 

armfloat

noun
  • An inflatable plastic band, normally worn on the upper arm, to help a wearer float in water and learn to swim. 

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