asleep vs aslumber

asleep

adj
  • In a state of sleep; also, broadly, resting. 

  • Inattentive. 

  • Having a numb or prickling sensation accompanied by a degree of unresponsiveness. 

  • Dead. 

aslumber

adj
  • Asleep. 

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