Uncovering and explaining how our digital world is changing — and changing us.

Big smartphones have finally eroded tablet usership.

Global tablet sales declined for the first time in 2015, but the number of tablets in active use is expected to decline for the first time this year, according to data in a new forecast by research firm Forrester.

Over the next five years, the number of tablets in use is expected to decline an average of 1 percent each year while the number of smartphones should increase by about 7 percent annually.

Big phones are to blame, especially in developing markets like China and India where most — 65 percent and 62 percent, respectively — smartphone owners have big screens, between 5 inches and 6 inches in diagonal (an iPhone 7 Plus measures 5.5 inches diagonally). Accordingly, just 6.4 percent of the population in China and 1.1 percent in India have tablets, according to Forrester.

Smartphones are often the primary devices for people in developing nations to connect to the internet, and it’s where smartphone sales are growing the fastest. Bigger smartphones let users complete a wider range of activities — and also obviate the need for tablets.

Tablet usage is higher in developed markets like the U.S. and EU5 (U.K., Germany, France, Spain, Italy) where only 33 percent and 23 percent, respectively, of online adult smartphone owners have big screens, according to Forrester. Unfortunately for tablets, 36 percent of smartphone users in those countries plan on buying a big-screen smartphone in the near future.

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