Maybe it's a good idea to somehow, somewhere prominently show last month's relay costs, broken down in those 3 area's so people have an idea of what it costs to host these relays and additionally show a "drive" of how much of these costs have been donated.

It's probably hard because you would have to do it client sided and all/most clients would have to implement this.

It's definitely not an end-all solution but giving insight in costs and covered costs at least gives people a general ballpark idea of what we would need to cover in the current situation and make it more likely to pay their part.