intermittent vs round-the-clock

intermittent

adj
  • Stopping and starting, occurring, or presenting at intervals; coming after a particular time span. 

  • Existing only for certain seasons; that is, being dry for part of the year. 

round-the-clock

adj
  • continuous; incessant; without interruption; all day long, 24 hours per day; nonstop: from the concept that it happens while the hands of the clock go all the way around. 

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