I'm trying to create fbceugene.com/2016

I want to create fbceugene.com/2016 and fbceugene.com/2017 etc but I've found that every time I try to, it modifies the URL of my pages to fbceugene.com/2016-2 even though I'm not using the year slug for posts and I have no other pages with those names.

Can you help?