Wouldn't these be averages calculated from a collection of answers?
I live in Western Europe and in some of the biggest cities, judging from the people I see out and about on the streets the native population seems to be a minority in large sections of the larger cities.
On the country-side it is rarer to see non-native people.
I can imagine that if some of these polls occurred in cities and that may be why the guesses are off when correcting for the lower percentages of immigrants outside the cities. The guesses may be accurate for the local region these folks live in but not accurate for the country as whole.
There's also the interesting point someone made here that in these numbers only foreign born people are counted as immigrants and not their children. The children of these people may be confused with immigrants by some of the native population. I guess it also depends on one's definition of "immigrant".
Is rational discussion already possible on this issue, or not yet? For decades anyone trying to talk about the issue of immigration was met with non-arguments intended to shut down discussion.
There even seem to have been cases of stochastic terrorism in some european countries. Seems like that sort of thing was bound to happen given how the corporate media / mockingbird media in "the west" has long demonized voices trying to bring nuance to this discussion about immigration.
Some of the folks trying to raise this issue may have been racists, but surely some of them weren't. And in any case it seems to me we should engage in civil discussion, not name-calling or lying about one's opponents no matter how strongly we may disagree. I can't help but recommend John Stuart Mill's On Liberty; the part about freedom of speech, in this context. Especially for those tempted to shut down discussion. Mill makes some arguments about censorship and how it can backfire relative to the professed goals of the censors. I think these arguments are worth taking into consideration by those tempted to shut down or prevent discussion.
I don't have strong opinions on this topic but the long-time taboo around raising any concerns or nuance around this issue does raise some red flags.