predecessor vs successor

predecessor

noun
  • A model or type of machinery or device which precedes the current (or later) one. Usually used to describe an earlier, outdated model. 

  • One who precedes; one who has preceded another in any state, position, office, etc.; one whom another follows or comes after, in any office or position. 

  • A vertex having a directed path to another vertex 

successor

noun
  • The next heir in order or succession. 

  • A person or thing that immediately follows another in holding an office or title. 

  • The integer, ordinal number or cardinal number immediately following another. 

  • A person who inherits a title or office. 

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