decare vs royal stremma

decare

noun
  • A unit of surface area equal to 10 ares (that is, 1,000 square metres, 0.10 hectares, or approximately 0.25 acres) 

royal stremma

noun
  • Synonym of stremma (“a decare”) 

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