2010 to 2015 on average about 15 fatalities in GA in the UK annually.
Air safety statistics in the EU - Statistics Explained
To give that a little context, 1730 road traffic fatalities in the UK annually (source - pretty much anywhere you look). And as we sadly know, this bank holiday claimed it's share on the roads, so as others have said, it's all, however tragic, par for the course.
As I was once told in a flight safety seminar ..." aircraft accidents are a statistical certainty. Your job is to make sure you're not one of the statistics".