如何从Google的Visualization API生成的条形图中删除x轴？

google.charts.load('current', {'packages':['corechart']});

function drawChart() {
  var data = google.visualization.arrayToDataTable([
    ['Year', 'Sales'],
    ['2013', 1000],
    ['2014', 1170],
    ['2015', 660],
    ['2016', 1030]
  ]);

  var options = {
    title: 'Company Performance',
    hAxis: {
      baselineColor: 'none',    // 设置x轴的基线颜色为无
      ticks: []                  // 移除x轴的刻度线
    },
    legend: 'none',
    bar: { groupWidth: '100%' },  // 设置条形图的宽度
    height: 400                   // 设置图表的高度
  };

  var chart = new google.visualization.BarChart(document.getElementById('barchart'));
  chart.draw(data, options);
}

<div id="barchart" style="width: 100%; height: 400px;"></div>

google.charts.setOnLoadCallback(drawChart);

hAxis: {
  ticks: []
}