but the 100 iq is always adjusted to the average of the population, you notice iq dropping when there's a large influx of population, in couple years the population stabilizes and the lowered average iq becomes the new 100, unless they also keep track of the iq inflation over the years, you won't know if the population actually got smarter or just the new average dropped so low that people previously considered as midbrains are now considered as above average