downer vs party pooper

downer

noun
  • Something or someone disagreeable, dispiriting or depressing; a killjoy. 

  • A livestock animal that has collapsed. 

  • A negative drug trip. 

  • A form of industrial action in which workers down tools and refuse to work. 

  • A drug that has depressant qualities. 

party pooper

noun
  • One who dampens fun; especially, one who declines to participate in or enjoy a party or some other group activity; one who does not agree with the opinions of a group. 

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