Additionally, it was only ever required for the general, open-for-all applicant pool (dubbed "off the street"). If you had certain qualifications or participated in a pre-training initiative, you were exempt (https://123atc.com/biographical-assessment). No idea what the distribution between "off the street" and other air controllers looks like, though.
EDIT: The next point might not be true. According to https://www.tracingwoodgrains.com/p/the-faas-hiring-scandal-... the introduction of the BA "blindsided and outraged" CTI schools (the pre-training mentioned below). END OF EDIT
Additionally, it was only ever required for the general, open-for-all applicant pool (dubbed "off the street"). If you had certain qualifications or participated in a pre-training initiative, you were exempt (https://123atc.com/biographical-assessment). No idea what the distribution between "off the street" and other air controllers looks like, though.