GlobalStats has reported that for the first time globally, mobile and tablet Internet use combined exceeded desktop Internet use. While the United States is trending that way, the lines haven't crossed yet and desktop is still the primary access tool for the Internet. You can check on countries individually on the GlobalStats website.
Part of the reason for this shifting, according to GlobalStats, is that, “Mobile compatibility is increasingly important not just because of growing traffic but because Google favours mobile friendly websites for its mobile search results.”
He pointed out that Google recently launched a tool where businesses can test their website mobile performance.
Google noted that users are five times more likely to leave a website if it isn't mobile friendly.