Carriers may be giving more shelf space to devices with larger screens, but many consumers could be waiting for a larger iPhone before they snatch up a “phablet.”   

According to new research from NPD Group, carriers in the United States devoted about a third of their shelf space to devices with a 4.7-inch or larger screen in the second quarter of this year. That’s up from just 4 percent in the second quarter of 2012.  

That said, Stephen Baker, vice president of industry analysis at NPD, noted that while interest among U.S. consumers in larger screen smartphones is growing, sales growth has been relatively disappointing over the past two years due to Apple’s dominance of the market with smaller phones. 

“All the demand, channel and usage pieces are in place for larger smartphone sales and share to increase,” Baker said in a statement. “If Apple releases a bigger iPhone it will be the final catalyst for explosive growth in the 4.7”+ market.”

NPD said that sales growth has lagged, however, behind product availability. U. S. sales of smartphones with 4.7-inch or larger screens now account for more than a quarter of sales, up from 2 percent in the same quarter last year. 

Bigger screen correlates with the use of more data. According to NPD Group, consumers with smartphones that have 4.7-inch and larger screens use about 4GB of data a month, twice that of consumers who own smartphones with smaller screens. 

“Larger screens mean a much richer content experience for smartphone users,” said Brad Akyuz, director of NPD Connected Intelligence. “The increase in video consumption driven by large-display smartphones is a tremendous revenue opportunity for network operators, as consumers will need more data to enjoy content on-the-go”.