WARC Data has partnered with GWI (formerly GlobalWebIndex) to provide media consumption data across a number of traditional and digital channels in 47 major markets, along with global and regional overviews, based on their consumer surveys of internet users aged 16-64. The data covers the online population that is aged 16-64, not the general population of each country.
More data on media consumption is available here, while information on GWI's survey methodology is here....