bottleneck vs tailback

bottleneck

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

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

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

verb
  • To slow by causing a bottleneck. 

  • To form a bottleneck. 

tailback

noun
  • A line of motor vehicles causing or the result of traffic congestion or a traffic jam. 

  • A running back or halfback who lines up furthest to the rear in an I formation. 

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