In some cases, such as with the Demographics module for Facebook Pages, specific criteria must be met for Facebook to return the necessary data to populate the module.

Facebook requires that at least 100 people must have engaged with your Page during the time period you've selected.

This means that, even if 100 people have liked your Page over the time period selected, if they're not allowing Facebook to share relevant information, such as their location, there aren't enough people for Facebook to return this demographic data to us.

The only thing we can advise to ensure this tab populates with relevant information is to select a longer period when it's more likely the Page has received 100+ likes from people who allow Facebook to share their information.