Everyone commits suicide at noon in view of everyone else. So the lowest possible number of blue eyed people go up one per day.
Here's a longer explanation:
Since people who know their eye color suicides at noon in plain sight of everyone else, we can set up induction.
If there's only one blue eyed person, they would suicide the first day at noon. Since everyone sees > 1 blue eyed people, they know this wouldn't happen. Since this doesn't happen, it's common knowledge that there is more than 1 blue eyed person. So if you only see one other blue eyed person, you must have blue eyes (but you don't know this yet because you see two blue eyed people).
On the second day, if there are only two blue eyed people, they would both suicide at noon. You see two blue eyed people. No one commits suicide because they either see two blue eyed people (if they have blue eyes) or three blue eyed people (if they don't). Now, everyone knows that there are more than two blue eyed people.
Since no one committed suicide the day before, you reason that there must be three blue eyed people, with the 2 people you see plus yourself. Thus, you know your eye color.
This is a bit long but I hope it's clear.