Face. Palm. Go back to school and take a statistics class, please.

If there is a given number of lightning fatalities per year (ie. your "a bit less than one"/year), there is also a (smaller) given number of lightning fatalities per hour. Given such a statistic - a consistent average of lightning fatalities per hour - it stands to reason that someone who is on a outside for more hours in a given time period is testing the odds more times in said given time period; exactly how someone who flips a coin twice is more likely to obtain a single tails than someone who only flips once (75% chance vs. 50% chance).



You are trying to show a correlation that more time on a bike causes more fatalities on a bike just as more time outside causes more lightening fatalities. The trick here is not showing off your mathematical prowess but in showing data that the more people are out biking the more fatalities there are. That is unless you are asserting statistics does not need any supporting data.