Obviously it is very difficult to determine how many users change from Windows to Linux, but some statistics published by the developers of Zorin OS, a popular distribution Linux, show that their distribution is attracting more and more users from platforms outside Linux.
More specifically, the developers of Zorin OS they mention that the latest update of their operating system was downloaded en masse by users using Windows and macOS.
"With over 900.000 downloads since its release nine months ago, Zorin OS 15 was our largest and most advanced release ever. Two out of every three of these downloads came from Windows and macOS, reflecting our mission to bring its power Linux to people who have never had access to it. None of this could have been possible without the help of you - the community - who advertise and help the project grow. We would like to thank all of you who made this release as great as it is! ”