asleep on the job vs lagging

asleep on the job

lagging

adj
  • Occurring after; indicating the later phase of 

  • Coordinate terms: concurrent, leading 

  • falling behind, not keeping up the pace 

noun
  • The covering of something with strips of felt, wood etc, either as insulation or for protection. 

  • A prison sentence. 

  • The material so used. 

How often have the words asleep on the job and lagging occurred in a corpus of books? (source: Google Ngram Viewer )