Company A- age nearest b'day so adjusting this with the age last birthday. Age nearest birthday for age last birthday 55 is 55 and 56. Each age contributes half population to exposed risk. Company B- death data matches with the cencus data. So the calculation nis straight forward. But you Ned to find the population on January 1st on 2012 and 2013 using population given on 31 march 2011, 2012, 2013. I used timeline to calculate this. Company C- age next for age 55 last is 56. Given population is at year end.
