Shell vs Sue

Shell

name

  • A diminutive of the female given name Michelle. 

  • A surname. 

Sue

name

  • A diminutive of the female given name Susan and of related female given names; popular as a middle name. 

noun

  • A Mary Sue (type of character in fiction). 

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