Mvc - ASP ActionFilters And Inheritance

All my controllers inherit from a BaseController that has an ActionFilter attribute:

[AnalyticsData]
public class BaseController : Controller {}
public class AccountController : BaseController {}
Some of my Actions in my controllers reuse the AnalyticsData ActionFilter:
public class AccountController : BaseController
{
[AnalyticsData(Page="AccountProfile")]
public ActionResult Profile()
{
// return View
}
}

I notice that the AnalyticsData ActionFilter only runs once. This is a good thing and I only want it to run once, but I'm wondering how that happens. If I set my breakpoint inside the OnActionExecuting:

public class AnalyticsAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext filterContext)
{
// break point set here
}
}

only gets hit once when AccountController serves it Profile view. How do ActionFilters and/or Attributes work that [AnalyticsData(Page="AccountProfile")] on the Action overrides/replaces [AnalyticsData] on BaseController?