That's about the proportion of the English population who, at the same time, elected not the King, who did very little, but the MPs who in effect chose the government. Moreover the last two Royal dynasties, the Stuarts and the Hanoverians, and the King who reigned between these dynasties, were elevated to the Throne by Parliament.... on the other hand, 15-18th Century Poland had an elective monarchy where the nobility (actually about 10% of the population) would elect the next King.
England has in effect been a Republic for a long time.