unemployment vs vacant hour

unemployment

noun
  • An instance or period of joblessness. 

  • The level of joblessness in an economy, often measured as a percentage of the workforce. 

  • The state of having no job; joblessness. 

  • A type of joblessness due to a particular economic mechanism. 

  • The phenomenon of joblessness in an economy. 

vacant hour

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