perky vs rocking

perky

adj
  • Lively. 

  • Standing upright; firm. 

rocking

adj
  • Excellent; great. 

  • Shaking, swaying or moving back and forth. 

noun
  • The abrading of a copper plate with a rocker, preparatory to mezzotinting. 

  • The motion by which the design on a steel mill is transferred to a copper cylinder. 

  • The motion of something that rocks. 

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