basement vs groundwork

basement

noun
  • A mass of igneous or metamorphic rock forming the foundation over which a platform of sedimentary rocks is laid. 

  • Last place in a sports conference standings. 

  • A floor of a building below ground level. 

groundwork

noun
  • The foundation; the basic or fundamental parts that support or allow for the rest. 

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