Perhaps even less than half. At my last job, only three of the ten people on my team were going into the office, and yet the rest of us were still perennially out of the loop.

That said, I don't think it has to be that way. Companies and teams do have the ability to choose their cultures and communication styles in an intentional way. It's just that very few actually do. And this is a situation where you absolutely do not want to accept the default configuration.