Your top five ranked locations appear in your location history according to how frequently and how recently you have used them. Also, locations that you have labeled in your My Locations list appear before unlabeled locations. This means that if you have five or more locations with labels, only the most recently and frequently used locations with labels will appear in the list, even if recently some of your unlabeled locations have been used more often. If you want to see an unlabeled location in this list, the way to do that is to give it a label.