What is the exact number for the Mendoza line?

“The Mendoza Line”, a term coined by George Brett to describe the boundary between mediocre and truly atrocious batting averages, was inspired by shortstop Mario Mendoza, who hit below .200 five times in his nine-year major-league career. Two different numbers are referred to as the Mendoza line: .200 is the most common, but .215 — Mendoza’s career batting average — is sometimes used.