In a recent article in the June 2011 issue of Media Planet, University of Virgina doctors discuss the severity of traumatic brain injuries and the difference it causes in men and women.
The article states that 3.8 million traumatic brain injuries a year more then likely stem from a concussion. And over 50,000 deaths in the U.S. are caused by traumatic brain injuries.
Link to full article http://tribads.chicagotribune.com/jump_pages/mediaplanet/0611/brainhealth.pdf