With smartphones quickly overtaking features phones, it should come as no surprise that more and more people are accessing the Web on their mobile devices, but just how people are we talking about?

According to new data(Opens in a new window) from the Pew Internet & American Life Project, about 63 percent of Americans with cell phones use those devices to access the Internet; 52 percent check email.

“Because 91 percent of all Americans now own a cell phone, this means that 57 percent of all American adults are cell Internet users,” Pew found. “The proportion of cell owners who use their phone to go online has doubled since 2009.”

About 34 percent of those who use the Web on their phones rely heavily on their phones for Internet access, Pew said.

“We call these individuals ‘cell-mostly internet users,’ and they account for 21 percent of the total cell owner population,” the study found. “Young adults, non-whites, and those with relatively low income and education levels are particularly likely to be cell-mostly Internet users.”

About 85 percent of those aged 18 to 29 use their phones to go online compared to 73 percent of those in the 30 to 49 age range, 51 percent of those 50 to 64, and 22 percent of those 65 and older.

“Notably, cell owners between the ages of 50 and 64 experienced a larger-than-average 15 percentage point increase in the past year,” Pew noted, up from 36 percent in the spring of 2012.

Pew polled about 2,252 adults between April and May for its study.