Tim Harford looks back at some of the most interesting numbers behind the news in 2015.

Tim Harford looks back at some of the most interesting numbers behind the news in 2015, from the migrant crisis to social media messages.

Contributors include: Professor Jane Green, Helen Arney, Paul Lewis, Andrew Samson, Leonard Doyle , Peter Cunliffe-Jones, Farai Chideya, Claire Melamed and Professor John Allen Paulos.