The mobile game continues to grow four years after release.

2019 marks the fourth year that Pokemon GO has been available to download across mobile devices. While you may have assumed that the game died out after the initial launch in 2016, the reality is a much different picture. The game is such a craze that there are even accounts for sale.

Last year, Pokemon GO saw users spending roughly $894 million. The previous "best year ever" for Pokemon GO was 2016...