Currently the Page User Demographics are all based on fans (which are the public Likes of a page). However, as with the New Page Experience likes are becoming less useful and everything is driving more towards following a page, it would make sense to include the same scopes but for followers, not just fans. For example:

page_fans
page_fans_locale
page_fans_city
page_fans_country
page_fan_adds
page_fan_adds_unique
page_fan_removes
page_fan_removes_unique*

All of these should have a new page_followers_* equivalent that allows to return demographic data on followers. From what we see if that Likes / Fans are pretty much stagnant now for big pages, but Followers are steadily growing as those are the main driver, but we are not able to register this growth via the API.