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

throw a monkey wrench in the works

verb

Synonym of throw a spanner in the works.

throw a spanner in the works

verb

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

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