decare vs dunam

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) 

dunam

noun
  • A modern Turkish unit of surface area equal to a decare (1000 m²), equivalent to the modern Greek stremma. 

  • An Ottoman Turkish unit of surface area nominally equal to 1,600 square (Turkish) paces but actually varied at a provincial and local level according to land quality to accommodate its colloquial sense of the amount of land able to be plowed in a day, roughly equivalent to the Byzantine stremma or English acre. 

  • Various other units in other areas of the former Ottoman Empire, usually equated to the decare but sometimes varying (as in Iraq, where it is 2500 m²). 

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