adrift vs fallen between cracks

adrift

adj
  • Floating at random. 

  • Absent from his watch. 

  • Behind one's opponents, or below a required threshold in terms of score, number or position. 

adv
  • In a drifting condition; at the mercy of wind and waves. 

fallen between cracks

How often have the words adrift and fallen between cracks occurred in a corpus of books? (source: Google Ngram Viewer )