census vs market research

census

noun
  • An official count or enumeration of members of a population (not necessarily human), usually residents or citizens in a particular region, often done at regular intervals. 

  • Count, tally. 

verb
  • To collect a census. 

  • To conduct a census on. 

market research

noun
  • The systematic collection and evaluation of data regarding customers' preferences for actual and potential products and services. 

How often have the words census and market research occurred in a corpus of books? (source: Google Ngram Viewer )