co-opt vs swallow up

co-opt

verb
  • To absorb or assimilate into an established group. 

  • To elect as a fellow member of a group, such as a committee. 

  • To commandeer, appropriate or take over. 

swallow up

verb
  • To take over or absorb something (especially an organisation) so it no longer has a separate identity; to assimilate. 

  • To completely enclose or envelop. 

  • To voraciously consume resources, such as money; to devour. 

How often have the words co-opt and swallow up occurred in a corpus of books? (source: Google Ngram Viewer )