I think Europe tends to split their findings by 50% or so.
I don’t know how it works in Denmark, but in England the government has the option to buy it (mostly if it is unique or museum quality) and they have to pay the finder the full amount that it is worth. This is to promote detectoring in order to find historical stuff.
The person that finds it usually has a deal made with the landowner ahead of time for some percentage of anything that they find. I forget what the typical rate is, but I think it is more in the 20% range, but perhaps 50/50 in some cases?