You might think of the feature phone, or "dumb" phone, as an outdated device that has been rendered obsolete by smartphones. However, a recent study from Pew Research Center found that among Americans who own a cell phone, 17% have feature phones. That usage increases at lower income levels. A quarter of Americans with annual income below $30,000 own feature phones, while the vast majority of those who earn $75,000 or more own smartphones. Data source: Pew Research. Chart by author. Feature phones remain popular with lower-income households because the devices and plans are cheaper. However, the study also found that 40% of users above the age of 65 use feature phones. That compares to 21% of 50- to 64-year-olds, 9% of 30- to 49-year-olds, and just 6% of 18- to 29-year-olds. Meanwhile, some younger users are replacing their smartphones with feature phones to avoid being constantly connected to the internet and work. However, smartphones and data plans are getting cheaper every year, so the feature phone's days remain numbered. Pew reports that 77% of Americans use smartphones, and that figure is likely to keep rising over the next few years. Offer from The Motley Fool: The 10 best stocks to buy nowMotley Fool co-founders Tom and David Gardner have spent more than a decade beating the market. In fact, the newsletter they run, Motley Fool Stock Advisor, has tripled the S&P 500!* Tom and David just revealed their ten top stock picks for investors to buy right now. Click here to get access to the full list! *Stock Advisor returns as of Feb. 5, 2018.The Motley Fool has a disclosure policy.