Bluebulb Projects' The Measure of Things presents:
4,500 is about 300 times the number of Living Kings and Queens
In other words, the count of Living Kings and Queens is 0.0033 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.