Blighty vs Letchworth Garden City

Blighty

name

  • Great Britain, Britain, or England, especially as viewed from abroad. 

noun

  • Synonym of Blighty one 

Letchworth Garden City

name

  • Synonym of Letchworth, Hertfordshire, England. 

How often have the words Blighty and Letchworth Garden City occurred in a corpus of books? (source: Google Ngram Viewer )