How do I initialize values/data in a LineChart using Controllers?

Question

I have an FXML file chart.fxml and a Controller class Controller.java for that FXML file. I wanted to make a LineChart using SceneBuilder, and initialize its data using a Controller.

However, when I run my program, the LineChart has no data/just shows the default LineChart.

This is my Controller.java class:

package exercise;

import javafx.fxml.FXML;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;

import java.util.HashMap;
import java.util.Map;

public class Controller {

    @FXML
    private LineChart<Number, Number> lineChart;

    void initData() {
        Map<Integer, Integer> map = initMap();
        NumberAxis x = new NumberAxis(
                map.entrySet().stream()
                        .min((p1, p2) -> p2.getKey() - p1.getKey())
                        .get()
                        .getKey(),
                map.entrySet().stream()
                        .min((p1, p2) -> p2.getKey() - p1.getKey())
                        .get()
                        .getValue(), 4
        );
        NumberAxis y = new NumberAxis();
        x.setLabel("Year");
        y.setLabel("Ranking");
        this.lineChart = new LineChart<>(x, y);
        this.lineChart.setTitle("Chart");

        XYChart.Series data = new XYChart.Series();
        data.setName("Ranks");
        map.forEach((key, value) -> data.getData().add(new XYChart.Data(key, value)));

        lineChart.getData().add(data);
    }

    private HashMap<Integer, Integer> initMap() {
        HashMap<Integer, Integer> values = new HashMap<>();
        values.put(2007, 73);
        values.put(2008, 68);
        values.put(2009, 72);
        values.put(2010, 72);
        values.put(2011, 74);
        values.put(2012, 73);
        values.put(2013, 76);
        values.put(2014, 73);
        values.put(2015, 67);
        values.put(2016, 56);
        values.put(2017, 56);
        return values;
    }
}

This is my Main class:

package exercise;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.stage.Stage;

import java.io.IOException;

public class Main extends Application {

    @Override
    public void start(Stage window) throws IOException {
        FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/chart.fxml"));
        window.setScene(new Scene(loader.load()));

        Controller controller = loader.getController();
        controller.initData();
        window.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

How do I fix this?