air raid vs onslaught

air raid

noun
  • A passing-heavy offensive scheme based on a shotgun formation with four wide receivers and a single running back. 

  • An attack on a surface target by aircraft. 

onslaught

noun
  • A fierce attack. 

  • A large number of people or things resembling an attack. 

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