around-the-clock vs persistent

around-the-clock

adj
  • All day and night; all of the time. 

persistent

adj
  • Indefinitely continuous. 

  • Of data or a data structure: not transient or temporary, but remaining in existence after the termination of the program that creates it. 

  • Describing a fractal process that has a positive Brown function 

  • Lasting past maturity without falling off. 

  • non-transient. 

  • Obstinately refusing to give up or let go. 

  • Insistently repetitive. 

How often have the words around-the-clock and persistent occurred in a corpus of books? (source: Google Ngram Viewer )