What is the demonym for a citizen of Niger?

If a citizen of Nigeria is a Nigerian, what is a citizen of Niger referred to as?

The Wikipedia article on Niger and the online Oxford Learner’s Dictionaries say that the proper term is Nigerien, as Vogel612 points out below. But The New York Times Manual of Style and Usage (1999) and Merriam-Webster’s Eleventh Collegiate Dictionary (2003) say that the proper name is Nigerois. And Merriam-Webster online now lists both Nigerien and Nigerois as correct forms. Is this simply a terminological difference between U.S. (or North American) English and British English, or is one word truly more appropriate than the other?

Solution 1:

The English Wikipedia page lists Nigerien (/niːˈʒɛəriən/).

Usually the guys over there are good with such stuff so I'd trust them with this one.

This is also backed up by the Oxford Learner's Dictionary and Wiktionary.

Solution 2:

When I find multiple conflicting usages, I like to see what other people are using. The NGrams data clearly shows a vast preference for Nigerien. A slate.com article which claims to have verified its facts with the Nigerien Embassay in the US says

What do you call someone who hails from Niger? Old-schoolers (and, in what an editor there called "something of an oversight," the Merriam-Webster Online Dictionary) still use the archaic "Nigerois" (nee-zher-WAH); more common and up-to-date is "Nigerien" (nee-ZHER-yen).

An NYT columnist who wrote an article about Nigeriens, was told by his editor that the NYT style manual prefers Nigerois to avoid confusion with Nigerians. But while in Niger he was told that nobody uses that word and so decided to stick with Nigeriens.

So stick with Nigerien, unless you are happy to sound archaic for the purpose of preventing confusion.

--

Google Ngrams gives the following usage:

If you wish to break it down by US/BR differences, you can:

US:

BR: