run time vs running time

run time

noun
  • The length of a film, television program or audio track in minutes, usually with end credits included 

  • The amount of time during which a program is executing. 

  • A software component designed to support the execution of computer programs. 

  • The stage during which a program is executing. 

running time

noun
  • The duration of a film or other recorded work. 

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