bottleneck vs throttle

bottleneck

verb
  • To slow by causing a bottleneck. 

  • To form a bottleneck. 

noun
  • The part of a process that is too slow or cumbersome. 

  • In traffic, any narrowing of the road, especially resulting in a delay. 

  • The narrow portion that forms the pouring spout of a bottle; the neck of a bottle. 

throttle

verb
  • To cut back on the speed of (an engine, person, organization, network connection, etc.). 

  • To utter with breaks and interruption, in the manner of a person half suffocated. 

  • To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate. 

  • To control or adjust the speed of (an engine). 

  • To breathe hard, as when nearly suffocated. 

  • To strangle or choke someone. 

noun
  • A valve that regulates the supply of fuel-air mixture to an internal combustion engine and thus controls its speed; a similar valve that controls the air supply to an engine. 

  • The lever or pedal that controls this valve. 

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