That's the theoretical maximum, in reality it's much much lower. For the sake of this comment I just visited a few random reddit pages, I saw:

2 adverts for reddit merchandise,

1 reddit flash game,

1 advert for reddit gold,

1 for a subreddit,

1 "thanks for not using adblock",

1 for the reddit ad system,

1 for a conference called poptech

and then on 3 pages I saw "sponsored links".