expropriate vs let alone

expropriate

verb
  • To deprive a person of (their private property) for public use. 

let alone

verb
  • To leave alone, let be; to stop bothering. 

conj
  • Much less; to say nothing of; used after one negative clause to introduce another, usually broader and more important clause, whose negation is implied by the negation of the first. However either of these instances mentioned can be applied with the use of let alone. 

  • not to mention, as well as; used after one item, to introduce a further item which is entailed by the first. 

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