The unemployment rate should be calculated by adding the products of two separate calculations.
First, the number of unemployed (people working less than 10 hours per week) should be calculated by dividing the total number of people seeking employment by the total adult population (ideally, age 20 and older, the age of majority). Next, underemployment should be calculated by dividing the total number of people seeking greater employment by the total population (both employed and unemployed) above the age of majority.
The total unemployment rate should be calculated by adding the unemployment rate to half the underemployment rate.