I don't know the answer to your question, but I'll answer it with a relative answer:
At least 25X the number of people you see online.
All the personalities you see on Facebook, CI, FE, all the other misc. fora, etc. are literally the TIP OF THE ICEBERG when it comes to the # of Trad Catholics.
And if you think the rest of the iceberg is less fervent, I have some more news for you.
Some of the most fervent Trads don't mess around with online fora. Maybe they don't like to argue, maybe they are too busy (quite common), etc.
Now I think there are benefits to a place like CI as well -- learning about the Faith, companionship with fellow Catholics (which not everyone outside Saint Marys gets to enjoy!), etc.
Nevertheless, I know plenty of Catholics personally who never go online. Male and female.
So all you single guys -- if you think there are no single female trads -- think again. You just have to go out searching IRL.