Drill-down column chart

by amcharts

HTML

<script type="text/javascript" src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/serial.js"></script>
<script type="text/javascript" src="http://www.amcharts.com/lib/3/themes/none.js"></script>
<div id="chartdiv"></div>

CSS

#chartdiv {
    width : 100%;
    height : 300px;
    font-size : 11px;
}

JavaScript

var chartData = [{
    "category": 2009,
    "income": 23.5,
    "url":"#",
    "description":"click to drill-down",
    "months": [
        { "category": 1, "income": 1 },
        { "category": 2, "income": 2 },
        { "category": 3, "income": 1 },
        { "category": 4, "income": 3 },
        { "category": 5, "income": 2.5 },
        { "category": 6, "income": 1.1 },
        { "category": 7, "income": 2.9 },
        { "category": 8, "income": 3.5 },
        { "category": 9, "income": 3.1 },
        { "category": 10, "income": 1.1 },
        { "category": 11, "income": 1 },
        { "category": 12, "income": 3 }
    ]
}, {
    "category": 2010,
    "income": 26.2,
    "url":"#",
    "description":"click to drill-down",
    "months": [
        { "category": 1, "income": 4 },
        { "category": 2, "income": 3 },
        { "category": 3, "income": 1 },
        { "category": 4, "income": 4 },
        { "category": 5, "income": 2 },
        { "category": 6, "income": 1 },
        { "category": 7, "income": 2 },
        { "category": 8, "income": 2 },
        { "category": 9, "income": 3 },
        { "category": 10, "income": 1 },
        { "category": 11, "income": 1 },
        { "category": 12, "income": 3 }
    ]
}, {
    "category": 2011,
    "income": 30.1,
    "url":"#",
    "description":"click to drill-down",
    "months": [
        { "category": 1, "income": 2 },
        { "category": 2, "income": 3 },
        { "category": 3, "income": 1 },
        { "category": 4, "income": 5 },
        { "category": 5, "income": 2 },
        { "category": 6, "income": 1 },
        { "category": 7, "income": 2 },
        { "category": 8, "income": 2.5 },
        { "category": 9, "income": 3.1 },
        { "category": 10, "income": 1.1 },
        { "category": 11, "income": 1 },
        { "category": 12, "income": 3 }
    ]
}];

var chart = AmCharts.makeChart("chartdiv", {
    "type": "serial",
        "theme": "none",
        "pathToImages": "/lib/3/images/",
     ...