Generation Age Group Population vs Labor Force

Does anyone know how to calculate Generation Age Group by employment? 

For example millennials are age 25-40 (according to PEW) their population is 695,765.  The employment age group is broken down as 25-34 = 301,706 and 35 to 44 = 284,359.  So the first age group of 25-34 is short six years and 35-44 is over by four years.  Is this doable?