Comment by thyristan

> I assume the denominator is cars registered with ADAC, rather than all cars in germany? Presumably that means those with lease contracts requiring another breakdown service wouldn't affect the stats?

Not quite, the denominator is the number of road-side assistance calls they get.

ADAC has a driver membership system, where you get that assistance for free as part of your membership as a driver. You can still call them as a non-member, and I suppose those calls will factor in the statistics as well, but that is expensive, so it's rare. And you don't register your car with them, so they don't know what their members are driving, you just tell them your membership number and can get assistance for whatever car you are currently driving in.