rumour vs whispering

rumour

noun

  • Britain, Canada, New Zealand, Australia, and Ireland spelling of rumor 

verb

  • Commonwealth standard spelling of rumor. 

whispering

noun

  • Something that is whispered; gossip; a rumor. 

adj

  • that whispers 

  • associated with whispers 

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