Translation:The majority of the inhabitants knew about the game.
It is all about citizenship.
Though "citizen" is used colloqiually as a synonym for "inhabitant" , the words actually have different meanings.
"A citizen of a country" have citizenship (is registered as a legal member of) in that country. e.g. "a canadian citizen"
An inhabitatant of a country, is one that lives in the country.
So if e.g. a canadian citizen lives in the USA, he is an inhabitant of USA but a citizen of Canada.