In 1998, as the US Dept. of Labor was about to introduce its new O*NET system of occupational classification, it released a list of 21 newer DOT occupations for which data had been collected (in 1991-1993) using the older DOT method of on-site direct observation described in the 1991 Revised Handbook for Analyzing Jobs. These new occupations (and some other adjustments to existing publications) were not published in a new printed release of the DOT, but rather were made available by fax and incorporated into electronic copies of the DOT.
SkillTRAN has incorporated these newer occupations into all of its products except its classic online services. The Social Security Administration recognizes these additional occupations as if they were included in the 1991 printing. The net increase raised the number of DOT occupations from 12,741 in the 1991 publication to 12,761 with these 21 additions (and one deletion).