nostalgic vs retro

nostalgic

adj
  • Of, having, or relating to nostalgia. 

noun
  • A person who displays nostalgia for something. 

retro

adj
  • Of, or relating to, the past, past times, or the way things were. 

  • Affecting things past; retroactive, ex post facto. 

noun
  • Past fashions or trends. 

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