When looking at records for individual articles. see:
Citation Benchmarking shows how citations received by this article compare with the average for similar articles. 99th percentile is high, and indicates an article in the top 1% globally. It takes into account:
Field-Weighted Citation Impact (FWCI) - the ratio of the total citations actually received by the denominator’s output, and the total citations that would be expected based on the average of the subject field.