Apple devices account for over 25% of visits to U.S. government websites

Nearly 17 percent of the 1.36 billion visits over that period were logged on iPhones or iPads, while 9 percent were on a Mac. Safari was the third-most popular browser, scoring a 20 percent share.

Microsoft's Windows continues to lead the way with 58 percent of visits originating on that platform, and Android is close on iOS's heels with 14 percent. Chrome —  which runs on virtually every platform —  is the most popular browser, followed by Internet Explorer.

The numbers come via the relatively new Digital Analytics Program, which provides unified analytics data to more than 300 government websites, including those run by the IRS, NASA, and the White House.

Apple's aggregate 26 percent share may not seem impressive on the surface, but it's a far cry from where the company was just eight years ago, before the introduction of the iPhone. In October 2006, the Mac's marketshare was just 6.1 percent, and the company had shipped less than one million Macs for the year.

At the end of 2014, marketshare had risen by just a couple of percentage points, but Apple shifted nearly 20 million Macs in the period —  including 5.5 million in the fourth quarter alone.

Meanwhile, iOS's status as the second-most used platform reiterates the seismic shift from desktop to mobile, catalyzed in large part by the iPhone and iPad. Mobile device users now make up 33 percent of the federal government's web audience.