IHS said there were 8.1 billion connected smartphones, tablets, personal computers, TVs, TV-attached devices and audio devices across the globe at the end of 2015.
IDC Russia said tablet shipments in the country fell by 8.5 per cent year-on-year to 919,000 units in the first quarter of 2016, while in terms of value in U.S. dollars the market shrank by 12.9 per cent.
The Western European PC and tablet market as a whole contracted by 13.7 per cent year-on-year in the first quarter.
Strategy Analytics said global smartphone shipments fell by 3 per cent year-on-year to reach 335 million units in the first quarter of 2016, marking the first time in history that this market has shrunk on an annualised basis.
The Middle East and Africa (MEA) tablet market declined 8.8 per cent year on year in the final quarter of 2015 to total 4.05 million units, according to latest figures from IDC.
The worldwide tablet market declined yet again in the fourth quarter of 2015 with 65.9 million units shipped, down 13.7 per cent year-on-year.
Gartner predicted that worldwide spending on devices including PCs, 'ultra mobiles', tablets and mobile phones will decline for the first time in 2016, although overall shipments are expected to increase slightly by 1.9 per cent to reach 2.4 billion units.
ABI Research predicted that 156 million tablets will ship in 2020, marking a 3 per cent CAGR for the device category between 2015 and 2020.
Tablet shipments in the Czech Republic slowed during 2015 on a year-on-year basis as the market became increasingly saturated and users also showed a growing preference for large-screen smartphones or "phablets".
Worldwide tablet shipments will reach 211.3 million units in 2015, down 8.1 per cent from 2014, according to a new forecast from IDC.