Be aware that Debian's xwayland depends on x11-common, so your number here will be the combined total of Xorg and Wayland.
You could try comparing xserver-xorg-core instead, but even then that'll only show you the number of submitters who have it installed, not the number that actually use it. The usual way to get a graphical desktop in Debian (task-desktop) pulls in both Wayland and Xorg, but uses the former by default.
The best estimate would be something like the number of xserver-xorg-core installs less the number of xwayland installs.
Using that method, it looks like there are roughly twice as many GNOME users as pure Xorg users.
