The following table summarizes the most recent operating system version numbers.

Operating system Version number
Windows 10= 10.0*
Windows Server 2019= 10.0*
Windows Server 2016= 10.0*
Windows 8.1= 6.3*
Windows Server 2012 R2= 6.3*
Windows 8= 6.2
Windows Server 2012= 6.2
Windows 7= 6.1
Windows Server 2008 R2= 6.1
Windows Server 2008= 6.0
Windows Vista= 6.0
Windows Server 2003 R2= 5.2
Windows Server 2003= 5.2
Windows XP 64-Bit Ed= 5.2
Windows XP= 5.1
Windows 2000= 5.0

Source:
https://docs.microsoft.com/en-us/windows/desktop/SysInfo/operating-system-version