That's just not true in my experience. We have two large corporate clients and one state agency that each require some level of IE6 support. I have a hard time believing these are the exception. I'd wager it's going to take a few more years to reach that point.
We have thousands of corporate clients and we tell them all the same thing: They can use any browser they like but it must be the latest / current version. Some of them grumble a bit but we've not lost a client because of IE6 in years.
So all of your clients (who use IE) are using IE9? I find this hard to believe, especially since many corporations are still running Windows XP, which will never get IE9.
That's just not true in my experience. We have two large corporate clients and one state agency that each require some level of IE6 support. I have a hard time believing these are the exception. I'd wager it's going to take a few more years to reach that point.