Jell-O vs Jello

Jell-O

name
  • A brand of dessert made from gelatin. 

  • Any brand of fruit flavored gelatin dessert mix. 

Jello

noun
  • A dessert made by boiling gelatin in water. 

How often have the words Jell-O and Jello occurred in a corpus of books? (source: Google Ngram Viewer )