get together vs split up

get together

verb
  • To start dating; to start being a couple. 

  • to agree 

  • to accumulate, to gather 

  • to meet, to gather together, to congregate 

  • Used other than figuratively or idiomatically: see get, together. 

split up

adj
  • Divided or separated. 

verb
  • separate, disassociate, cause to come apart. 

  • Cease to be together, break apart from the group. 

How often have the words get together and split up occurred in a corpus of books? (source: Google Ngram Viewer )