occurrent vs ongoing

occurrent

noun
  • An event, something that occurs. 

  • One who comes to meet another. 

adj
  • Pertaining to occurrence; having to do with an occurrence. 

  • Current, actual, occurring. 

ongoing

noun
  • Something that is going on; a happening. 

adj
  • Continuing, permanent, lasting. 

  • Presently or currently happening; being in progress. 

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