In reply to kevin stephens:
I did some research into this for my dissertation a while back.
Statistically, on single pitch routes climbers are more likely to wear helmets when climbing trad. The reason for this, is 'to protect their head from falling objects' (which are rare on single pitch crags, and much more likely in a mountain environment).
The fact is, that most impacts to helmets are caused by falling, not by falling objects. Sport climbers are inherrently more likely to fall than their trad counterparts, as the very nature of sport climbing is closer to the limit of the climber.
This is why helmets with good all round protection (foam style as opposed to ecrin roc style) are better for sport climbing, as they are much better at absorbing impacts in areas other than just the crown of the helmet.
Unfortunately, there are few helmets which offer such good all round protection, because the british standard around which all helmets are designed is too generic and 'mountaineering' orientated.
Good to hear you're ok though!