Intelligence itself is a very complex and diverse topic, the different manifestations of which will not be subject to the same sets of genes. Is it smart to be a fantastic chef? Inventing new dishes and flavor combinations? Is it smart to be a nuclear physicist? Is it smart to be a neurosurgeon? Is it smart to be a virtuoso musician? Is it smart to be a painter? What if the painter paints abstracts? Is it smart to be a writer? What if the writer touches and moves the minds and emotions of billions?
In my view, all of these are intelligence, and all of them are likely the result of very different gene combinations mixed with unique personal experiences. So the notion that there is an "intelligence" is not really true, there are a large number of aptitudes that fall within the space of "intelligence". So there is no hard and fast measure of how it "varies" between ethnicities, because it's a hypersurface across an n-dimensional space. You can't describe it as up or down, higher or lower. At best, for your purposes, you could describe it, on average, as morphing.
It's also, in my view, very much folly to try to capture this and quantify it with a 5 minute series of questions entirely focused on one subject.
Edit:
I just have to capture this thought while I'm thinking about it. Intelligence is also something that I think is not entirely genetic. We know that the human brain changes physically due to experience and stimulus. Intelligence (and the brain in general) should be thought of partly as a muscle, which can be grown and developed, and which can atrophy.
So if you're trying to measure the intelligence of an ethnicity (not that ethnicity really exists in a clean way), you're in part trying to measure the quantities and types of experiences of those ethnicities. And that's something that's going to change over time.