Given that Pokemon Go broke about every imaginable app store record over the summer, it shouldn't be a surprise that the game was recently named as Apple's most popular app in 2016. Apple mentioned that Pokemon Go was its most downloaded app in 2016 in a press release released yesterday on its website.
Apple also noted the success of Super Mario Run in the press release, citing its phenomenal 40 million downloads over the course of just 4 days. Despite being released in mid-December, Super Mario Run also finished in Apple's ten most downloaded apps for 2016.
Pokemon Go and Super Mario Run represent a strong 2016 showing for Nintendo, which waded into mobile gaming this year. Although Nintendo didn't see much profit from Pokemon Go (as the game was developed by Niantic Labs, a separate company), Super Mario Run definitely gave Nintendo's year end numbers a giant jolt.
As for Pokemon Go, the game has periodically appeared at the top of the Apple Store's running "top grossing" list even after hype surrounding the game died down. Niantic Labs has recently run several successful events and introduced new Pokemon to the game, which has helped keep interest in Pokemon Go high.