If your administrator enabled Age-Based Retirement and imported the ages for employees, Workforce calculates their ages for the age band calculations. Click Attrition Data by Age Band to set attrition data by age band. For each year, you can enter the number of headcount/FTE you anticipate leaving the company. Because attrition data reduces supply resources, enter the data as negative percentages (for example, -.05). The data you enter here reduces the summary FTE.