OK a serious answer then.
The statistics show that generally traffic accidents are rising but in the scheme of things road riding is not hugely risky; I am unable to find any stat's for MTBing to compare against, so it's impossible to give you an accurate answer ... but generally, there's no surprise in learning that you're best off in a car but don't even think about touching a motorbike and if you're pushing your bike, best get back on it, as there's slightly better odds when you're a cyclist than a pedestrian:
http://www.guardian.co.uk/news/datablog/2012/sep/28/road-deaths-great-britain-data
... but of course, you know what they say about statistics

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