In among the numerous announcements being made at Microsoft's Build developer conference, the company has revealed that Windows 10 is now found on just under 700 million devices. A statistic that means the operating system has seen nearly 200 million extra installs in the last 12 months.

Back at Build 2017, Microsoft said Windows 10 was installed on 500 million devices. That figure had reached 600 million by November and is now "almost" at the 700 million mark.

When Windows 10 launched in 2015, Microsoft said its aim was to have the OS installed on one billion devices by the year 2018. A year later, the company admitted that it was overly optimistic and that more time was needed to hit this target, but the number of new installations continues to grow at a steady rate.

While PCs make up most of the Windows 10 devices, the figures include tablets, notebooks, Xbox consoles, the Hololens headsets, Surface Hub systems, phones, and IoT products.

Despite edging ever closer to three quarters of a billion installs, Windows 10 remains behind Windows 7 as the second most popular version of Microsoft's OS. NetMarketShare has the older platform running on 43.57 percent of systems, while Windows 10 has a 33.81 percent share. Thanks to the number of enterprise users and its popularity in China, Windows 7 remains ahead, but the gap keeps shrinking. Security updates for Windows 7 will cease in early 2020, which should result in Windows 10 installs increasingly rapidly.

A figure that's likely to be even more pleasing for Microsoft relates to its Office 365 service, which now has 135 million monthly active commercial users.