Hart Island is a Nightmare. I applaud the efforts of the Project in attempting documentation for burials since 1980 but also recognize it is a massive effort laden with many more issues than I can contemplate. Having said that, I'm not seeing the numbers you are
@victoriarobinson642, I'm seeing less than a 1000 with "unknown" search and only a couple with "Doe". Please help me see what you are.
Many years ago, and gratefully it has changed, coroners and other agencies had great difficulty in entering partial remains cases because of required data fields in NCIC; they simply did not have the info to enter. Additionally, again some time ago, the OCA (Originating Case Agency) entering the info into NCIC had to annually Verify the case was still open Or it would be purged from the system. I am aware of agencies who re-entered the info into NCIC once they realized this had occurred, however, who knows what may have been lost in terms of possible matches that were also not verified and thus potentially purged.
If you are in a state with satellite ME offices, you cannot assume that all of the cases for the state have been entered or were previously entered. Combine this with the difference between coroner and medical systems varying by state and location within, elected position vs hired, experience, education, etc - all of this adds to the problem. I'm providing a link here that shows a graphic of the systems across the US plus some general info - this is a 2011 NPR article and graphic - so while changes will have likely occurred, the point can be made that this was only 14 years ago.
https://www.npr.org/2011/02/03/131242432/graphics-how-is-death-investigated-in-your-state
Much has changed since the inception of Namus (which I believe started sometime around 2005), cases of which were often entered by volunteers who had developed a relationship with an agency and were simply assisting by entering the data and noting the appropriate agency contact info with their final sign off before the record was published. Legislation (both in requiring agencies to submit to Namus and also changing their laws regarding unidentified remains), funding for all kinds of associated efforts, etc., have definitely all helped and much of that has been as a result of grass roots efforts among the families of the missing and other champions of the cause. DNA technology has grown tremendously bringing some answers, some agencies are resubmitting fingerprints (the integrated AFIS was not computerized until almost 2000 by the FBI), dental info previously entered is being reconfirmed or corrected as necessary by forensic odontologists, etc
Anything you can do makes a difference (searching what is available, searching news archives for cases - particularly pre internet, learning/help change your states rules/laws around UIDs, etc).