The International Data Corporation (IDC) has released a new report suggesting that PC shipments will drop more than previously expected.

The IDC report indicates that Worldwide PC shipments are estimated to fall by -10.1 percent in 2013, which is slightly below the previous projection of -9.7 percent. Furthermore, the report also highlights that global PC shipments may drop by another -3.8 percent in 2014.

PCs are facing stiff competition from portable devices such as tablets, and PC demand has been rapidly decreasing in the recent years. The report also suggests that two-in-one devices, which let customers use the device in a clamshell as well as in a slate configuration, are also giving PCs a hard time.

"Perhaps the chief concern for future PC demand is a lack of reasons to replace an older system," said Jay Chou, Senior Research Analyst, Worldwide Quarterly PC Trackers at IDC. "While IDC research finds that the PC still remains the primary computing device - for example, PCs are used more hours per day than tablets or phones - PC usage is nonetheless declining each year as more devices become available. And despite industry efforts, PC usage has not moved significantly beyond consumption and productivity tasks to differentiate PCs from other devices. As a result, PC lifespans continue to increase, thereby limiting market growth."

A big chunk of PCs worldwide run on Windows operating system. Many of the tablets and two-in-one devices are also available on the Windows platform, which gives users similar features and functionality of working on a PC.  

The IDC report also noted that the worldwide Windows-based tablet shipment is also estimated to increase to 39.3 million units in 2017 compared to less than 7.5 million units in 2013 and less than just 1 million units in 2011.

The drop in the worldwide PC shipment has a direct effect on companies such as Intel, which produce chips for PCs, and PC makers such as HP, which has had to lay off many workers in its struggle to remain in business..