Bluebulb Projects' The Measure of Things presents:
30 is about two times the number of Living Kings and Queens.
In other words, the count of Living Kings and Queens is 0.50 times that amount.
(2015 figures) (distinct Monarchs) As of 2015, the world has fifteen Kings and Queens reigning over 45 countries. Of all these, Queen Elizabeth the II is the only reigning Queen; she has monarchical authority over the sixteen of the Commonwealth nations.