The worse problem is IE8, which is the highest supported version on XP, and is a way bigger piece of crap than IE9... especially with XP's still high market share.
http://arstechnica.com/information-technology/2014/03/weeks-...
http://arstechnica.com/information-technology/2014/03/weeks-...
For our product (enterprise task and workflow management), we see about 2% IE6/7 and about 5% IE8 in our customer base. Of those customers, most are planning to upgrade away from XP sometime in the next year or two.