Source : Webster's Revised Unabridged Dictionary (1913)

Demography \De*mog"ra*phy\, n. [Gr. ? the people + -graphy.]
   The study of races, as to births, marriages, mortality,
   health, etc. -- {Dem`o*graph"ic}, a.

Source : WordNet®

demographic
     adj : of or relating to demography; "demographic surveys"
     n : a statistic characterizing human populations (or segments of
         human populations broken down by age or sex or income
         etc.)