forced vs spontaneously

forced

adj
  • Produced by strain; not spontaneous; unsincere. 

  • Opened or accessed using force. 

  • Obtained forcefully, not naturally. 

spontaneously

adv
  • In a spontaneous manner; naturally; voluntarily. 

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