everglade vs swampland

everglade

noun
  • A tract of marshland, especially one containing clumps of sawgrass and hammocks of vegetation 

swampland

noun
  • Low-lying land that is regularly flooded; especially such land that is drier than a bog or a marsh. 

  • The set of effective low-energy physical theories that are not compatible with quantum gravity. 

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