How many Social Security Disability and SSI claimants do not file an appeal ?

It's fairly common knowledge that the majority of social security disability and ssi disability claimants do not file an appeal following a denial. In my former capacity as a disability examiner this was often verified by how many "uniques" an individual had; in other words, how many times a person had opted not to appeal but rather to file a brand new disability application (however, I probably