The Cardiff metropolitan area makes up over a third of the total population of Wales, with a 2016 population estimate of about 1,100,000 people - https://en.wikipedia.org/wiki/Cardiff.

Saturday's 16,000 attendance = 1.5% of 1.1m. Expressed a different way = abject.

The club can't flog nearly enough season tickets, hence it's too embarrassed to publish the total number sold.