Windows 10 was released in July as a free download to all Windows 7 and Windows 8.1 users, but many are sticking with the operating system they already have and not upgrading to the new one.

Windows 10 was registered at a 9.96 percent share of all Web traffic generated by computers by the tracking company NetMarketShare in December, CNet reports. That rate is only slightly higher than the 9 percent share the operating system had in November.

When Windows 10 was first released, Microsoft was pleased with the quick surge of upgrades by Windows 7 and Windows 8.1 users.

The NetMarketShare data is a much different take than Microsoft has on the adoption rate of Windows 10. Microsoft said on Monday that more than 200 million devices worldwide (including tablets and smartphones) are using Windows 10. Microsoft also said that since Black Friday, more brand new devices with Windows 10 installed have been activated.

Windows 10 is approaching the same usage as Windows XP and Windows 8.1, according to the NetMarketShare data. Windows XP is now out of Microsoft's support range, meaning it will not receive critical updates and Windows 8.1 was extremely unpopular among many users. Windows XP and Windows 8.1 users are almost forced to upgrade to Windows 10.

But, most users who still use Windows 7 are sticking with it. Around 55 percent of web traffic in the NetMarketShare data came from computers using Windows 7.

Microsoft first called Windows 10 an optional upgrade and sent frequent popups to Windows 7 and Windows 8.1 users. The popups still come to these users, but now Microsoft is calling the upgrade "recommended."

Microsoft worked hard to release a clean operating system with Windows 10. They heard the complaints users had in Windows 8 and advertised Windows 10 as an operating system that would work across multiple devices. In Windows 10, Microsoft introduced the Edge browser and added support to the digital voice assistant Cortana.

Microsoft wants users to have Windows 10 to make sure that, if they buy a printer or video game in the future, it will work for them.