After eliminating reviewers without conflicts or potential conflicts with the authors, editors have a smaller pool of qualified potentials reviewers. Even then only a subset of those potential reviewers will be available and agree to perform the evaluation. So the final number is even smaller. Credit: Nancy R. Gough, BioSerendipity
Read more: N. R. Gough, Guidelines for Suggesting Reviewers. BioSerendipity (12 November 2018). https://www.bioserendipity.com/guidelines-for-suggesting-reviewers.