obtain vs perseverate

obtain

verb
  • To get hold of; to gain possession of, to procure; to acquire, in any way. 

perseverate

verb
  • To cause the perseveration of (a given reflex or response). 

  • To persist in doing something; to continue to repeat an action after the original stimulus has ended. 

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