Amazon says it had the best holiday season ever, with its own Echo home assistantt he best seller.

Amazon reports that it shipped more than a billion items globally with the Amazon Ec

o assistant and the Echo Dot topping the list of best sellers.

Amazon sold nine times the number of Echo devices it sold last year. Amazon executives said it was difficult to keep them in stock.

Other top sellers included the movie “Finding Dory,” Samsung Electronic’s VR virtual reality headset, and Nintendo’s Pokemon Sun and Pokemon Moon role-playing video games.

In a statistic we found surprising, 72 percent of Amazon customers used mobile devices to shop.

Prime customers, who get free two-day shipping as well as access to Amazon’s music and movie libraries, spent twice as much as other consumers.