I'm not a huge facebook fan, but I use it sometimes for IM chat to keep in contact with some people.
As i'm at a loose end just now I thought i'd look at peoples types and see if there's a correlation with socionics.
Approximately 15% of them I am uncertain of.
The remaining 85%
Works out in rounded up percentages:
So it does show a massive preferential for Delta, 75% in total.
There are a couple of odds and ends in the uncertain category I suspect are IEI.