What's selling better: iPhone 6 or iPhone 6 Plus?

Apple's first phablet, the iPhone 6 Plus, has been well received by consumers, but its smaller-screened cousin is far outperforming in terms of sales, according to new research.

AppLovin, a mobile advertising firm, estimates that the 4.7-inch iPhone 6 accounts for 80 percent of new iPhones in use globally, with the 5.5-inch screen iPhone 6 plus taking the remaining share.

The firm, which processes 25 billion ad requests daily, looked at the high volume of data to ascertain its estimate. "Since interaction and usage differences between the 6 and 6 Plus on our network are negligible, it's fair to estimate that roughly one in five new iPhones sold is an iPhone 6 Plus," AppLovin said in a blog post on its website.