The headline unemployment rate is calculated by dividing the unemployment level for those aged 16 and over by the total number of economically active people aged 16 and over.
Cyfrifir y brif gyfradd ddiweithdra drwy rannu’r lefel ddiweithdra ymhlith y rheini sy’n 16 oed a throsodd â chyfanswm y bobl 16 oed a throsodd sy’n economaidd weithgar.