angle for vs pull strings

angle for

verb
  • To try to obtain something by subtle indirect means: political manoeuvres, suggestion, etc. 

  • Used other than figuratively or idiomatically: see angle, for. 

pull strings

verb
  • To manipulate a situation, especially by asking favours of others; to use one's influence with others to attain a desired goal. 

  • To control a person, organization, or situation by operating behind the scenes, as a puppeteer controls a marionette. 

How often have the words angle for and pull strings occurred in a corpus of books? (source: Google Ngram Viewer )