The assessment itself is here: https://www.iucnredlist.org/species/194052138/200522253 https://www.iucnredlist.org/species/194052138/200522253 - it does take in

The assessment itself is here: https://www.iucnredlist.org/species/194052138/200522253 https://www.iucnredlist.org/species/194052138/200522253 - it does take into account the uncertainty in the data and the fluctuations; it concludes that the population has declined by 22-72% over the last 10 years. The threshold in this situation for Endangered is 50% (for Vulnerable, 30%, and for Critically Endangered, 80%) so the upper end is taken on a precautionary basis to lead to the Endangered assessment.