On my History Review page there are approximately eight pages, each with 50 items, where the names of two moderators dominate the close review. In over 400 reviewed posts, I counted the names of only five reviewers who are not moderators.
Only 20 of these 400 posts were reviewed by users who are not moderators. For example, the following is on page 6.
The second most prolific mod whose name appears is Glorfindel
This continues up to the present day, June 1, 2020. Obviously there is a drastic shortage of reviewers on ELL, and it is admirable that the two mods have undertaken the thankless task of clearing up the review queue.
They did it for the good of the community, the backlog has been dealt with great success but maybe it's time to step back and allow other users to review?