This discussion always comes up and nobody has any hard data. Neither do I.
But we do know that it is much easier for companies to contribute to existing GPL codebases. Yes we have Apple releasing some things under BSD, and some companies in the firewall, routing, and storage business but even taken together doesn't match the long list of every single Linux release.
This reality simply does not reflect that "companies prefer BSD". There is absolutely a lot of software for which it works well, but it is not a license for everone. Many other things, such as community building, may even be more important.