Bill Allombert announced today via the Debian-devel mailing list that the X86_64 version of Debian has now surpassed all of the other supported architectures by a narrow margin. The most surprising part of this announcement however, and accompanying info-graphics provided on the Debian Popularity Contest page, is that this was not already true.
Thanks to PAE support is Debian kernels dating back to 2010, the i386 architecture had been given life support, finally allowing for systems to break through the 32-bit 4GB memory ceiling. PAE support allows for 64-bit Intel and AMD processors to dedicate the maximum addressable memory to individual applications, while still executing 32-bit code exclusively.
From the Debian-devel mailing-list: