backtracking vs regress

backtracking

noun
  • The act of one who, or that which, backtracks; a retracing of one's steps. 

  • The usage of a runway as a taxiway, especially at private strips and smaller airports. 

  • The act of building all possible solutions to a problem incrementally, abandoning any candidate solution if it cannot lead to a valid solution. 

regress

noun
  • The act of passing back; passage back; return; retrogression. 

  • In property law, the right of a person (such as a lessee) to return to a property. 

  • The power or liberty of passing back. 

verb
  • To move backwards to an earlier stage; to devolve. 

  • To move from east to west. 

  • To perform a regression on an explanatory variable. 

  • To interrogate a person in a state of trance about forgotten elements of their past. 

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