如何在Chart.js饼图中将小时格式更改为百分比

<canvas id="myChart"></canvas>

var data = {
  labels: ['任务1', '任务2', '任务3'],
  datasets: [{
    data: [8, 12, 4],
    backgroundColor: ['red', 'blue', 'green']
  }]
};

var options = {
  tooltips: {
    callbacks: {
      label: function(tooltipItem, data) {
        var dataset = data.datasets[tooltipItem.datasetIndex];
        var total = dataset.data.reduce(function(previousValue, currentValue) {
          return previousValue + currentValue;
        });
        var currentValue = dataset.data[tooltipItem.index];
        var percentage = Math.floor(((currentValue / total) * 100) + 0.5);
        return percentage + "%";
      }
    }
  }
};

var ctx = document.getElementById('myChart').getContext('2d');
var myChart = new Chart(ctx, {
  type: 'pie',
  data: data,
  options: options
});