outputting all info from child nodes

I need to output all the information from a nodes children that are not empty.

What I have currently(not working): Country/State/cities/city[string-length() != 0]/

Each city element has 4 child nodes: name, population, size, foundingDate.

I need to print all info for all the cities of all the states, but only the values that aren't null.

Odd sounding, I know.

What would be the proper way to do this?

EDIT: This is how the xml is formed. (I had written the path line above wrong, but fixed it.) Of course there are multiple State and City elements.

<Country>
  <State>
    <Name>stateName</name>
    <Cities>
      <City>
        <Name>cityName</Name>
        <Population>popNum</Population>
        <Size>citySize</Size>
        <foundingDate>foundingYear</foundingDate>
      </City>
    </Cities>
  </State>
</Country>

The objective is to output all the City info for the Country that does not have empty values. (The xml value isn't completed, but still needs to be searched.