"Inbreeding decreases as the pedigree is traced back suggesting a time dependent increase in population-wide inbreeding." Another chart shows how much total genetic contribution certain well know breeding horses have in the current population. For example, Hrafn fra Holtsmuli contributes .106 (I believe that means he shows up in over 10 % of modern Icelandic horse pedigrees) in Icelandic bred horses. The mare Síða from Sauðárkrókur is second on the list at .066. Other influential stallions are, in order, Orri from Þúfa, Ófeigur from Flugumýri, Fengur from Eiríksstaðir, Þáttur from Kirkjubær , etc.