In the last 2-3 years, there have been a number of changes in the ways that deaths are reported to the Social Security Administration and in the ways that the SSDI is made available to the public. I have been finding that more and more often, I find an obituary and no SSDI entry ever appears. Not just that the SSN itself is redacted, and that some of the SSDI databases are not updated as often as they used to be, but some deaths are never included.
I put together the following chart, which shows the effect. (counts are from Ancestry.com)
Has anyone gone into more detail to determine which states are under-reporting?