A new Pew Research Center study examines a week in the life of American smartphone users. While its findings were numerous, one note that stands out is the dependence on smart phones among low-income Americans and those with minimal education.

Ownership has risen exponentially in recent years. 64 percent of adults now use smartphones — up 29 percent from just four years ago. 13 percent of responders to the survey reported a $30,000 annual household income or less.

Moreover, the study reports that 10 percent of those who responded do not have broadband access at home, thus relying more heavily on their phone’s data plan. Dependence is even higher among American youth between ages 18 and 29.

Inversely, less than one percent of households making over $75,000 annually depend on smart phones for internet access.

In terms of demographics, Pew found that just four percent of whites were considered smartphone-reliant, as opposed to 12 percent of African-Americans and 13 percent of Latinos.

The study was based on 3,181 telephone conversations.