Final answer:
In 2005, contingent labor accounted for over 16.6% of total employment in the US.
Step-by-step explanation:
In 2005, the use of contingent labor accounted for over 16.6% of total employment in the US. This data is based on the information provided, which states that 18.6 million employees were in contingent labor, representing 16.6% of the total employed.