I've heard that the situation you describe is common in Silicon Valley. Based on my personal experience in Sydney, Australia, the distribution is about a 40/40/

I've heard that the situation you describe is common in Silicon Valley. Based on my personal experience in Sydney, Australia, the distribution is about a 40/40/10% Win/Mac/Linux. I've seen about the same amount of companies giving either Mac or Windows as the default, and almost always people can request a different OS if there is a specific need. In all other countries where I've worked (Italy, Thailand, Indonesia, Brazil) it's more like 80% Windows. I'm basing this on my direct experience in companies I've worked at, I don't have statistical data.