I have met this question couple of times in my job-seeking experience. From various companies from various countries (CH, DE, AT).
What is really funny, that in each of the case, it was when I was living in my homeland
So what kind of value could this info give to the recruiter? no idea.
I was earning about 19k Euro (that time about 23K CHF) per year, but in totally different economical reality.
However, when question is just stupid when stated to some abroad-living person, I think it can be even rude when stated to insider. While the only purpose I can figure out is not to give you as much as you would ask for. For example if you change the company and would like to earn 100k instead of 86k, tehy will give you just 94, saying that it is already an increase for you.