It looks like College Board has release new Subject Test percentiles covering the 2017-2019 graduating classes - https://secure-media.collegeboard.org/sat/pdf/sat-subject-tests-percentile-ranks.pdf
The header still says “ A student with a Literature score of 600, for example, can see that 40% of test takers scored lower” even though 600 in literature says 38. And checking the provided URL for definitions to try to clarify shows the page doesn’t exist.
This apparent lack of quality control is concerning for an organization with such influence over college admissions.