decouple vs disunite

decouple

verb
  • To unlink; to take or come apart. 

  • To muffle the seismic waves of (a nuclear explosion) by performing it underground. 

disunite

verb
  • To disintegrate; to come apart. 

  • To cause disagreement or alienation among or within. 

  • To separate, sever, or split. 

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