If you thought people were glued to their smartphones already, just wait: App Annie projects that the total number of hours spent using mobile apps will rise to 3.5 trillion hours by 2021, up from the already considerable 1.6 trillion hours logged last year.

The average user in France spends just over 1.5 hours per day using mobile pass, compared to more than 3 hours per day in South Korea.

All that screen time adds up to lots of revenue in the form of app sales, in-app advertising and mobile transactions. Added together, App Annie says the mobile app economy drove $1.3 trillion in spending last year, a figure that should approach $6 trillion by 2021, again including app purchases, advertising and mobile purchases.

Data: App Annie; Chart: Andrew Witherspoon / Axios