Solitary practice leaves no coven roll, initiation record or central registry by design, and religious landscape surveys count Wiccans and Pagans as one combined category rather than separating solitary eclectic practice from initiatory lineages.
What would resolve this A large-scale self-identification survey that asked Wiccans specifically whether they practice solitary and eclectically, rather than within an initiatory lineage, would let a real estimate be drawn where only a combined Wiccan/Pagan figure exists today.
OpenWikipedia contributors, Eclectic Wicca (Wikipedia)