According to researcher IDC, tablet sales improved 78.4% worldwide in 2012 and are on track to improve 48.7% this year to 190 million units sold.

In data released this week, the firm also predicts that tablets will be the fastest-growing device category between now and 2017, outselling desktop PCs this year and laptops beginning in 2014. Overall, IDC expects the market for connected devices to grow 8.5% annually over the next five years, and that's despite slowing growth in PC sales.

"In emerging markets, consumer spending typically starts with mobile phones and, in many cases, moves to tablets before PCs," said Megha Saini, research analyst for IDC's Worldwide Smart Connected Device Tracker, in a press release. "The pressure on the PC market is significantly increasing and we can see longer replacement cycles coming into effect very soon and that, too, will put downward pressure on PC sales."

Other key findings and predictions from the report:

  • Worldwide, Apple (NASDAQ:AAPL) claimed 20.3% of connected device shipments -- and 30.7% of revenue -- in the fourth quarter. Samsung was the volume leader and ranked second in revenue share.

  • Emerging markets led growth last year. Overall shipments rose 41.3% in 2012 while tablet shipments more than doubled. Smartphone sales improved 69.7% in emerging markets.

  • The worldwide market for connected devices grew 29.7% in 2012 and will advance 21.2% this year. By 2017, IDC predicts the total market will surpass 2.2 million devices sold, resulting in $814.3 billion in revenue.