campaign vs go out on the knocker

campaign

noun
  • The period during which a blast furnace is continuously in operation. 

  • A series of operations undertaken to achieve a set goal. 

verb
  • Consistently ride in races for a racing season. 

  • To take part in a campaign. 

go out on the knocker

How often have the words campaign and go out on the knocker occurred in a corpus of books? (source: Google Ngram Viewer )