There's no data on this because no company discloses how many contract workers they use. The DOLabor last studied this in 2005. The best data is from the software companies that manage these programs for Fortune 1000 companies and they say it is 35% -distributed among agency temps, ICs, consulting companies and part time. The report is behind a signup requiring business email http://www.fieldglass.com/resources/reports/2015_2016_state_...