According to a forecast update from the International Data Corporation (IDC) Worldwide Quarterly Mobile Phone Tracker, smartphone shipments are expected to grow 3.1% in 2016, which is a substantial slowdown from the 10.5% growth in 2015 and 27.8% in 2014. 
Shipments are expected to hit 1.48 billion in 2016 and grow to 1.84 billion in 2020. 
The new forecast is 2.6 percentage points lower than IDC's previous forecast for 2016 on the basis of the continued slowdown in mature markets and China. 
IDC expects large markets like the United States, Western Europe, and China to see low single digit growth rates in 2016 while Japan and Canada are expected to contract by 6.4% and 6.9%, respectively. 
In all these markets, smartphone buying behavior is changing in many ways. In operator-driven markets the transition away from two year subsidized contracts toward monthly installment plans are slowly taking place. Meanwhile, many retail heavy markets are seeing a surge in the eTailer channel, better known as online marketplaces.

Source : QNA