Real world article
(written from a production point of view)
According to a PADD created for Star Trek: Insurrection, but only seen from the back in the finished movie, the Evora (at that point called Bartisi) had a ruling caste which comprised 3% of their population. The remaining 97% of the population made up the working caste, who elected the regent and other governing officials from the ranks of the ruling caste.