*Cattle, buffaloes, goats, and sheep.
Human population was predicted using the FAOSTAT estimated population for 2017 and projected population for 2018. A constant rate of growth over this period was assumed. Ruminant population size was predicted using FAOSTAT world livestock data from 1961-2016. See FAOSTAT Methods & Standards for details on how livestock numbers are assessed. We estimated ruminant livestock totals in 2017 and 2018 separately for each species using non-seasonal Holt-Winters exponential smoothing models. The counter assumes a linear increase in livestock numbers from 2017 to 2018. As of 2017, there are approximately 0.51 ruminants per person.
Human and livestock counter developed by Chris Wolf () and William Ripple ().