At Google's developer conference, it said it paid $5 billion to developers in the past 12 months. Independent analyst Jan Dawson charted out his estimate of what that looks like on a quarterly basis, and compared it to his estimates for payouts to developers from Apple.
As you can see, Google is quickly closing the gap on Apple, though it still lags considerably. Google has 1 billion monthly active users on Android. Apple has ~500 million. With twice as many users, Google should have more revenue than Apple from app sales.
Chart via Statista
Business Insider/Statista