According to a new report from eMarketer, 4.55 billion people worldwide will use a mobile phone in 2014, while the global smartphone audience is expected to reach 1.75 billion (it surpassed the 1 billion mark in 2012). The report also suggests that smartphone adoption will dramatically increase through 2017. Nearly two-fifths of all mobile phone users are projected to use a smartphone at least monthly this year. That’s close to one-quarter of the total worldwide population.

“Mobile adoption is slowing, but new users in the developing regions of Asia-Pacific and the Middle East and Africa will drive further increases,” reports eMarketer. “Between 2013 and 2017, mobile phone penetration will rise from 61.1 percent to 69.4 percent of the global population.”

The report — “Worldwide Mobile Phone Users: H1 2014 Forecast and Comparative Estimates” — projects a fast-paced trajectory through 2017 for smartphone adoption, with global smartphone penetration among mobile phone users reaching 50 percent by the end of the forecast period.

“More than 2.23 billion people worldwide, or 48.9 percent of mobile phone users, will go online via mobile at least monthly in 2014, and over half of the mobile audience will use the mobile Internet next year,” notes eMarketer. “Mobile data network expansion — especially in areas outside of urban centers in emerging markets with rising middle classes — and the adoption of smartphones and feature phones with Internet capabilities will fuel growth of the mobile phone Internet consumer base. We estimate that the total number of mobile phone Internet users will rise 16.5 percent in 2014 and maintain double-digit growth through 2016.”