Yes, you read that well. Google employees don't like to eat their own food. It seems like one third of the entire Google workforce doesn't use Google+: 32.6% haven't posted anything at all in the last month. A depressing stat for the Mountain View search engine and eyeglasses company.
The other numbers are not much better: 20.5% of them haven't touched their Google+ page in the last 3 months, while 12.9% haven't posted anything in the last six months.
Of course, you can argue that maybe they are only sharing stuff in private, with their friends. And, without knowing their Facebook usage, the number may not be that meaningful. Perhaps the Googlers who don't use it don't like to use any social networks at all.