function drawChartTreatmentsPerYear() {
  var chartData = google.visualization.arrayToDataTable([
    ['Series', 'Number of Treatments'],
    ['2022', 2],
    ['2021', 8],
    ['2020', 1],
    ['2015', 2],
    ['2014', 1],
    ['2011', 1],
    ['2004', 1],
    ['2000', 1],
    ['1999', 3],
    ['1991', 1],
    ['1990', 3],
    ['1988', 1],
    ['1984', 2],
    ['1983', 1],
    ['1981', 2]
  ]);
  var chartOptions = {
    pieHole: 0,
    title: 'Treatments per Year (n=30)',
    fontSize: 'automatic',
    doWeHaveDanglingCommas: 'No ;-)'
  };
  if (window.customizeGoogleChartOptions)
    customizeGoogleChartOptions(chartOptions, 'TreatmentsPerYear', 'pie', 15, 0);
  var chart = new google.visualization.PieChart(document.getElementById('chartDivTreatmentsPerYear'));
  chart.draw(chartData, chartOptions);
}
google.load('visualization', '1', {'packages': ['corechart']});
google.setOnLoadCallback(drawChartTreatmentsPerYear);