Complex sentence: This includes people who work as freelancers, consultants, independent contractors, temps, part-timers, contingent employees and who are otherwise self-employed, a segment of workers that makes up one-third of the American workforce.
Split into simpler sentences: This includes people who work as freelancers, consultants, independent contractors, temps, part-timers, contingent employees and those who are otherwise self-employed. This segment of workers makes up one-third of the American workforce.