Almost 10,000 Microsoft employees used iPhones to access the company’s email system last year, according to two people who told the Wall Street Journal that they heard the estimate from senior executives. That’s approximately 10 percent of Microsoft’s global workforce, and it doesn’t take into account employees who have iPhones but don’t access their Microsoft email with their devices.

With few exceptions, such as J Allard, who is the chief experience officer for Microsoft’s entertainment and devices division, most of Microsoft’s senior executives frown on iPhone use, according to the Wall Street Journal. During a retreat last March, for example, CEO Steve Ballmer said he grew up in Detroit, where his father worked for Ford and his family always drove Fords, and COO Kevin Turner noted that he discouraged salespeople from using iPhones, saying: “What’s good for the field is good for Redmond.”

Employees interviewed by the Wall Street Journal said that those lower on the org chart tend to use iPhones openly around each other, but will hide them from senior executives. “Maybe once a year I’m in a meeting with Steve Ballmer,” said one. “It doesn’t matter who’s calling, I’m not answering my phone.”