apply oneself vs get down to business

apply oneself

verb
  • Synonym of strive: to work hard, to complete an activity with good effort and focus. 

get down to business

verb
  • To commit oneself to a task or activity that is employment-related or that requires serious effort or concentration. 

How often have the words apply oneself and get down to business occurred in a corpus of books? (source: Google Ngram Viewer )