@Override
  public String getValue() {

    List<Node<VisOverlayNode, VisOverlayEdge>> nodes =
        Controller.getModel().getOverlayGraph().nodes;

    int totalNeighbors = 0;

    for (Node<VisOverlayNode, VisOverlayEdge> node : nodes) {

      totalNeighbors += node.edges.size();
    }

    if (nodes.size() == 0) return null;

    double result = (double) totalNeighbors / (double) nodes.size();

    return new DecimalFormat("#.0").format(result).toString();
  }