-A lot of Jewish women wear wigs, because of religious reasons. They hide their hair, with a scarf, a sheitel, or a wig.
Sheitel (...) is the Yiddish word for
a wig or half-wig worn by some Orthodox Jewish married women in order
to conform with the requirement of Jewish Law to cover their hair.
This practice is part of the modesty-related dress standard called
Source: wikipedia "Sheitel".
-For the non-religious part, if the wig is well-made, normally, you don't now the person wears a wig, so you probably can't say how many people you meet wearing a wig.
We don't know the amount of muslim women wearing wigs, among those who doesn't wear the hijab, as not everybody agrees on the modalities of the interdiction, some says it's only for real human hair, some islamic scholar says it's not lawful (but even more when wigs are made of real human hair) based on:
“Allah has cursed the woman who adds hair extensions and the woman who
asks for it to be done.” [Sahîh al-Bukhârî (5934) and Sahîh Muslim
The exception being when the women lose her hair making them bald.
Wigs made of human hair are permitted when there is a real need for them, like if a woman's hair falls out all of the sudden or if she is naturally bald. In this case, she is covering up a substantial and abnormal blemish in her appearance.
The permissibility for this can be gleaned from the permission the
Prophet (peace be upon him) gave to
Arfajah b. Sad to wear a gold
nose after his real nose was cut off in battle. [Sunan Abî Dâwûd
(3696) – authenticated by al-Albânî in al-Silsilah al-Sahîhah (18
-For the historical part, we don't really know who were the people who wore wigs, as it doesn't seem to be precised, and there are no historical evidence for a particular people, probably a lot of people. The fact there are Islamic restrictions that doesn't exist in some other religions, make it "imitating".
There's another question arising here: hijab with wig, is it compatible? I don't know, but this question looks interesting.