In software? I'd say about 50-60 in S1 and going down to like 30-40 in S3, but a high percentage none the less.
Outside of software, you will probably get to 70+%.
It's not just a facebook problem, its a problem of a lot of large orgs with large salaries and "prestige" associated. People get in just to use it as a "platform" to launch their career, they bring their status and political games with them, read books such as "How to win fake political friends and push your influence to others" and then implement them. They lack real visions, ideas or venues of productivity, so they delegate and communicate and call meetings and push ideas and agendas that only serve to give them the "upper hand" when its promotion time.
Just check out Facebooks internal network, where you gotta play nice and play politics or you will be look down on as "not having community spirit".