Total Stake
The total stake of those that attended represents a whopping 42% of the entire stake of the Steem Blockchain. Of course a large part of this is sitting in the public Accounts of Steemit Inc.
How much was there when the Steemit Inc accounts are excluded?
There is a split a little further down. Witnesses 5.1m others 2.9m but that is based on the accounts that checked in at the event.
So including Steemit Inc, at least 40% of the whole network stake was present in person. Excluding Steemit Inc from both sides of the equation, about 5% of the network stake was in attendance. Maybe more given the possibility of closet whales.
That's it based on the data I had available.