The Fighter is among the most popular D&D 5e classes at every tier. The data available from DnDBeyond (official and unofficial) make its popularity unquestionable.
Official (2019).
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The most recent is
unofficial.
Quasi-official data is also seen here in ENWorld.
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This survey is asking a different kind of question. It is about the character concept of a nonmagical warrior.
The actual DnDBeyond data seems publicly available, in light of the unofficial source. It can be done, but looks like it would take some effort to determine the precise frequency of DnDBeyond players who are building and updating strictly nonmagical Fighters.