6.2 billion – the number of smartphones & tablets on the planet by 2020, says App Annie

Data from App Annie suggests that the total number of smartphones and tablets on the planet will hit 6.2 billion by 2020 – up from 2.6B today. That would be 80% of the forecast population of 7.76B people.

The analytics company told Bloomberg that the strongest growth will be seen in India, Indonesia, China, Mexico, Brazil and Turkey as cheaper phones hit the market. For many of those in developing countries, the post-PC era has already arrived, a smartphone or tablet serving as their only Internet-enabled device …

The company says that global mobile app revenue will hit $50B this year, and $101B by 2020. Total annual downloads will rise from 111B last year to 284B by 2020.

Apple’s iOS is set to retain its store leadership by gross revenue over the five-year period, while Google Play and third-party Android stores will expand their lead measured in downloads due to wider proliferation of devices.

The firm suggests that China will overtake the U.S. in app revenue in the first half of this year, noting that China already overtook the U.S. in downloads early last year, but lower average prices mean that it will take a little while longer for revenue to catch up.

We did our own roundup of the best affordable phones of last year, and the five manufacturers to watch this year.