The largest market for the Apple iPhone has been the US, but it appears China could be taking over. A larger percentage of people in the US have iPhones, but the size of the market in China means sales can be higher in that market. UBS analysts are reporting China could have been responsible for 36 percent of iPhone sales in Q4 2014.

Apple will announce its quarterly earnings on Tuesday. UBS claims the US was responsible for an estimated 24 percent of sales. Just one year prior, the US brought in 29 percent of iPhone sales and China brought in 22 percent. This change is the result of around 2 million additional iPhones being sold in China over America.

The iPhone 6 was one of the first Apple devices to get a quick wide release across multiple Chinese carriers. Plus, a rising income level for people in the market means more people can afford a premium device like the iPhone.