Southerner vs lowlander

Southerner

noun
  • A resident of the American South, often specifically a white resident of the American South. 

  • Synonym of Confederate: a citizen of the Confederate States of America. 

lowlander

noun
  • One who lives in the lowlands. 

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