It also depends on the kind of site. The more the operator thinks you should be using a desktop, the worse it is.
Yeah one non-profit is a place that people physically so I imagine a lot of people look at it on their cell phone. We have over half of our visitors on mobile.
iOS is important in all rich countries, and if you want to address wealthy people in developing markets. It is very important for these reasons.
In Europe Safari has decent 21%.
Thus I would not neglect Apples web browser but calling it very important is going a step to far in my opinion.
One in five is not enough to be very important? I disagree.