heirdom vs heritability

heirdom

noun
  • An inheritance or succession. 

heritability

noun
  • The condition of being inheritable 

  • The ratio of the genetic variance of a population to its phenotypic variance; i.e. the proportion of variability that is genetic in origin 

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