In this page you can see United States unemployment rate . United States unemployment rate.
It is the percentage that expresses the proportion of unemployed in US compared to the total active population:

United States unemployment rate = total unemployed United States / United States active population

Unemployed is a worker who don´t have a employ.

Clicking on the links in the table you can get more information.

US risk premium is the spread between 10-year USA Government Bonds (T-bond).

Definition of USA risk premium is the increment in interest rates that investors have to be paid for loans and investment projects in Unites States compared to some standard country .