Farmer class is by far the most common, accross all of history (unless, of course, you are the Mongols).
Also in many religions/cultures the three you listed aren’t distinct groups, so they only have 2/3 – in Islam for instance, clergy and elite can be the same person (the Caliph being the main example), while in Tengri tribes warrior and elite are the same thing, and in Japanese Buddhism warrior and clergy are the same thing.
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