Distribution of the online audience of independent.co.uk in GB 2016, by age group

The source adds the following information:
"The percentage of this property's total audience that meets the given demographic criteria.

Calculations
We directly collect anonymous web and app usage data through the publishers and networks that use Quantcast Measure and have placed our pixel on their properties. We combine this with reference data from a small set of seed data, allowing our statistical models to accurately infer the demographic segments of a property's audience in aggregate."