Apple iPad shipments are on the decline amid a worldwide slowdown for tablets which could signal the end of the boom of the popular consumer and enterprise devices.

Shipments of all tablets worldwide will increase by just 7.2% this year, compared to 52.5% in 2013, according to a projection from research firm IDC. Tablet shipments this year will total 235.7 million.

The numbers reflect widespread reliance on PCs and smartphones for computing and communicating. Buying trends show that consumers and businesses still look to run full-fledged applications on PCs, which have experienced a jump in sales recently.

Otherwise, users are hanging on to tablets longer than expected, which is one reason for the slowdown in tablet shipments, IDC said. Tablet refreshes were expected every two to three years, but owners are holding on to devices for three years and longer, IDC said. New software can run on old devices, and there is no compelling reason for tablet owners to upgrade, IDC said.

IDC's numbers include hybrid devices that are mainly tablets, but can also be laptops when needed with keyboard attachments. The increase of shipments of such devices, which mostly run Windows 8, was just 4%.

IDC is projecting shipments of Apple's iPad to be 64.7 million units this year, a decline of 12.7% compared to 2013. Apple has reported declines in iPad shipments in recent quarters, but iPhone and Mac shipments increased in the most recent, October fiscal quarter.

As expected, Apple CEO Tim Cook has expressed hope that iPad shipments will return to growth. Apple could get a major boost through a enterprise partnership with IBM to deliver mobile devices with customised cloud, management and analytics software.

Android and Windows device shipments, however, are increasing at the expense of iPads. Shipment of tablets with Android will reach 159.5 million units in 2014, growing by 16%. Samsung, Lenovo, Asus, Amazon and others sell Android tablets.

The shipment of Windows tablets and hybrids totalled 10.9 million, growing by 67.3%. Microsoft's Surface Pro 3 is the most well-known device Windows tablet.

IDC is projecting tablet shipments to continue slowing down into 2018, when yearly growth will be just 5.4%. But the research firm also noted that Windows 10, Google's operating systems and Apple's product expansion were "unknowns" that could impact tablet shipment numbers.