keel over vs turn over

keel over

verb
  • To collapse in a faint; to black out, to swoon. 

  • To die. 

  • Of a vessel: to roll so far on its side that it cannot recover; to capsize or turn turtle. 

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 keel over and turn over occurred in a corpus of books? (source: Google Ngram Viewer )