Increase in number of mobile users over the past year.
The latest study looked at more than 350,000 mobile phone users over an 18-year period.
However, Places was really designed with the mobile user in mind.
It's based on figures from 42 major countries which he says cover 72% of the world's mobile phone users.
There are about 18 million mobile phone users in Afghanistan.
The game has already been download by more than 60 million mobile phone users.
In addition, excerpts of books are also available to mobile phone users.
Now it is owned by more than 100,000 mobile users worldwide.
The Philippines already has more mobile phone users than personal computers.
"It's tough to say why mobile users are more willing to pay," he said.
