::::: I have a more radical suggestion:  cut the entire sentence except for the first clause about there being 16 Commonwealth realms. Notwithstanding the “longstanding” presence of these other statistics, they really don’t belong.   

 ::::: As Wikipedia:Manual_of_Style/Lead_section correctly says, the introduction should define the topic, make clear why it is notable, and briefly outline the major points of the article.  Except for this sentence, it does it quite well.  But the stuff about combined area and population is completely unrelated, both to the rest of the introduction and to the body of the article.  It says nothing about what Commonwealth realms are, why the reader should care about them, how they relate to each other or how they came into being.  It’s just a couple of arbitrarily chosen statistics, no more relevant than GDP or average rainfall. 

 ::::: I’m proposing to delete this material entirely, unless for some reason there is a true consensus for keeping it regardless of the Manual of Style.  For very similar reasons I’m proposing to delete the two columns in the table about size and population of the individual realms, which tell the reader nothing about each realm as a realm.  Anyone who wants to know those (or other) statistics about a particular realm ought to be able to find them in the article about that realm, and is unlikely to choose this article as the first place to look.