Google charts - trend charts on a bar chart

I am trying to plot a trendline on a column chart. But the lines are not displayed. Please refer to the jsfiddle https://jsfiddle.net/sashant9/m04py64w/

I used "trendlines: {1: {}, 2: {}}" according to google charts documentation.

Please check the code below.

    function drawVisitorGraph() {


        var data = new google.visualization.DataTable();
        data.addColumn('string', 'Date');
        data.addColumn('number', 'Search Visitors');
        data.addColumn('number', 'Unique Visitors');

        data.addRow(["2015-07-01",1774,3266]);
        data.addRow(["2015-07-02",1891,3017]);
        data.addRow(["2015-07-03",1572,2730]);
        data.addRow(["2015-07-04",979,1604]);
        data.addRow(["2015-07-05",1024,1702]);
        data.addRow(["2015-07-06",2163,4097]);

        var chart = new google.visualization.ColumnChart(document.querySelector('#visitor_graph'));

        var options = {
                bars: 'vertical',
                vAxis: {format: 'decimal'},
                trendlines: { 1:{},2:{}}, 
                width: '100%',
                height: '100%',
                colors: ['#070979', '#EC0F13']
            }
            chart.draw(data,options);

    }

    //google.setOnLoadCallback(drawChart);

    google.load('visualization', '1.1', {packages: ['corechart'], callback: drawVisitorGraph});