The US Census Bureau classifies abstractors as Occupation No. 541191, and lists  info as to abstract companies with no. of employees, title companies, searchers, etc. A ton of info can be found at https://factfinder.census.gov/faces/tableservices/jsf/pages/productview.xhtml?src=bkmk 

  It will be interesting to see if the numbers of abstractors fade out in the next census, as Artificial Intelligence and the changes in the industry occur, where so many title companies aren't doing the detailed searches, just doing a "quickie search."

MN Requires licensing of abstractors, and we're a dying breed. They have been pulling people out of retirement to do complex searches, ( a retired friend just came out of retirement to do an abstract for the Minnesota VIkings Stadium for example) because there aren't any qualified people,