mull vs turn over

mull

verb
  • To work (over) mentally; to cogitate; to ruminate. 

  • To chop marijuana so that it becomes a smokable form. 

  • To dull or stupefy. 

  • To powder; to pulverize. 

  • To heat and spice something, such as wine. 

  • To join two or more individual windows at mullions. 

noun
  • An inferior kind of madder prepared from the smaller roots or the peelings and refuse of the larger. 

  • A stew of meat, broth, milk, butter, vegetables, and seasonings, thickened with soda crackers. 

  • dirt; rubbish 

  • A thin, soft muslin. 

  • A promontory. 

  • A snuffbox made of the small end of a horn. 

  • The gauze used in bookbinding to adhere a text block to a book's cover. 

  • Marijuana that has been chopped to prepare it for smoking. 

turn over

verb
  • To mull, ponder 

  • To cause extensive disturbance or disruption to (a room, storage place, etc.), e.g. while searching for an item, or ransacking a property. 

  • Used other than figuratively or idiomatically: see turn, over. 

  • To generate (a certain amount of money from sales). 

  • To spin the crankshaft of an internal combustion engine using the starter or hand crank in an attempt to make it run. 

  • To produce, complete, or cycle through. 

  • To flip over; to rotate uppermost to bottom. 

  • To transfer. 

  • To give up control (of the ball and thus the ability to score). 

  • To relinquish; give back. 

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