We have crime data going back to December 2010 and populations can change quite quickly. We now have a full set of annual official estimates for the small area Lower Layer Super Output Areas (LSOAs) and Middle Super Output Areas (MSOAs). The very latest available year is 2017, we expect to see 2018 in the Autumn. Population is essential to calculating crime rates or crime rates per hectare (a unique UKCrimeStats feature) to deflate/inflate the impact of crime relative to the size of the resident population.