I stand corrected. The time frame when God's name stopped being pronounced was, according to :The Jewish Encyclopedia of 1901, Volume 11, page 353
"SIMEON
THE JUST
():
High
priest. He is identical either with Simeon I. (310-291 or
300-271
b.c.), son
of Onias I., and
grandson of Jaddua, or with Simeon II.
(219-199 b.c.), son of Onias II... After Simeon's death men
ceased
to utter the tetragrammaton aloud (Yoma 30b; Tosef Sotah.
xiii.)"