throw a spanner in the works vs throw a wrench in the works

throw a spanner in the works

verb
  • To introduce a problem, dilemma or obstacle, something unexpected or troublesome. 

throw a wrench in the works

verb
  • Synonym of throw a spanner in the works. 

How often have the words throw a spanner in the works and throw a wrench in the works occurred in a corpus of books? (source: Google Ngram Viewer )