944b How Prevalent Are Current Appraisal Waivers?

Appraisers seem to worry about whether or not they will have a job in the future and one of the contributing factors is appraisal waivers. But, how prevalent are they? We seem to be in a slow down, but is that because Fannie and Freddie are turning to waivers? https://www.aei.org/research-products/report/prevalence-of-gse-appraisal-waivers/