Religious landscape surveys count Wiccans and Pagans as one combined category, and small, private, initiatory covens are not registered anywhere that would let a researcher isolate the Alexandrian line from other Wiccan traditions.
What would resolve this A study that surveyed self-identified Wiccans on which initiatory lineage, if any, they belong to, of the kind Pagan studies scholars have occasionally run for specific regions, would let a tradition-specific estimate be drawn where only a combined one exists today.
OpenRonald Hutton, The Triumph of the Moon: A History of Modern Pagan Witchcraft