shrivel vs shrivel up

shrivel

verb
  • To become wrinkled. 

  • To collapse inward; to crumble. 

  • To draw into wrinkles. 

shrivel up

verb
  • To become completely shriveled; to completely dry up and become wrinkled. 

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