Why so few shots/goals from distance?

So many Palace goals this season have been from close range - in fact, other than Townsend's against Stoke, I'm struggling to remember anything from outside the 18-yard box. Why don't our players shoot more from further out? Is it a sign of low confidence? Lack of ability? Or something else?

Don't get me wrong, I'm grateful for anything that goes in the opposition net. ;) But I'm a bit mystified by the apparent reluctance to hit long-range screamers.