With all of the trouble Research in Motion has been going through over the last two years, the one area that the company has been able to hang their hat was in the corporate mobile workforce.   The latest iPass Global Mobile Workforce Report , however, shows that the BlackBerry no longer reigns as the top smartphone used by business users and that the iPhone is now king of the hill.

According to the report 45% of mobile workers use an iPhone compared to just 31% in 2010.  The BlackBerry, however, fell from 34.5% last year to 32.2% in 2011.  The BlackBerry, right now isn’t really losing share, but, the platform isn’t growing with the pace of the industry at large.

What may be even worse for RIM is that mobile workers are buying their own smartphones as consumers to use at work in increasing numbers.  42% of mobile workers in 2011 are liable for their own device compared to just 34% in 2010 and these pro-summers are overwhelmingly not buying BlackBerry devices.