Plural or Singular Navigational Menu Options?

In our system we have what you would call a List Screen, where a user can view a list of objects. For example Phone Numbers. A user can add as many Phone Numbers as they want. Right now to get to these List Screens using the menu the labels are singular. So it would say "Phone Number".

I am wondering if this is incorrect? To me having the labels singular makes it seem like there is only one. Are there best practices for using singular vs. plural when naming navigational menu options?

Example of some List Screen options in our Navigation Menu: