Percentage of how many accidents are caused by cellphones?

Answer 1

Cellphone causes an average of 1.4 million car crashes every year, of those 200,000 crashes are due to text messaging

here is the link that have other reports and numbers related with this topic

http://www.datashelves.com/how-many-car-accidents-are-caused-by-drivers-who-are-texting

The problem is that these numbers are ESTIMATES; in most cases, people won't admit to texting or emailing on their cell phones during an accident. And simply TALKING on the phone is associated with only a minor increase in accidents.

This blends in with the entire subject of "distracted driving", where the distraction is anything that takes your attention off the road; changing radio stations, yelling at the kids in the back seat, reaching for a soda or a snack, going to sleep or "zoning out" while driving; these are all part of the same problem. I've seen many women applying their makeup while driving, and many men who shave while driving.

Answer 2

Simply because people take phone calls as they are driving and then look at their screen and don't look where they are going and crash.