decouple vs uncouple

decouple

verb
  • To unlink; to take or come apart. 

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

uncouple

verb
  • To disconnect or detach one thing from another. 

  • To come loose. 

  • To loose, as dogs, from their couples. 

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