V3: Bar clustered

HTML

<script src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="http://www.amcharts.com/lib/3/serial.js"></script>
<div id="chartdiv" style="width: 100%; height: 362px;"></div>

JavaScript

var chart;

var chartData = [{
    "year": 2005,
        "income": 23.5
}, {
    "year": 2006,
        "income": 26.2
}, {
    "year": 2007,
        "income": 30.1
}, {
    "year": 2008,
        "income": 29.5
}, {
    "year": 2009,
        "income": 24.6
}];


AmCharts.ready(function () {
    // SERIAL CHART
    chart = new AmCharts.AmSerialChart();
    chart.dataProvider = chartData;
    chart.categoryField = "year";
    chart.startDuration = 1;
    chart.plotAreaBorderColor = "#DADADA";
    chart.plotAreaBorderAlpha = 1;
    // this single line makes the chart a bar chart          
    chart.rotate = true;

    // AXES
    // Category
    var categoryAxis = chart.categoryAxis;
    categoryAxis.gridPosition = "start";
    categoryAxis.gridAlpha = 0.1;
    categoryAxis.axisAlpha = 0;

    // Value
    var valueAxis = new AmCharts.ValueAxis();
    valueAxis.axisAlpha = 0;
    valueAxis.gridAlpha = 0.1;
    valueAxis.position = "top";
    chart.addValueAxis(valueAxis);

    // GRAPHS
    // first graph
    var graph1 = new AmCharts.AmGraph();
    graph1.type = "column";
    graph1.title = "Income";
    graph1.valueField = "income";
    graph1.balloonText = "Income:[[value]]";
    graph1.lineAlpha = 0;
    graph1.fillColors = "#ADD981";
    graph1.fillAlphas = 1;
    chart.addGraph(graph1);

    // second graph
    var graph2 = new AmCharts.AmGraph();
    graph2.type = "column";
    graph2.title = "Expenses";
    graph2.valueField = "expenses";
    graph2.balloonText = "Expenses:[[value]]";
    graph2.lineAlpha = 0;
    graph2.fillColors = "#81acd9";
    graph2.fillAlphas = 1;
    chart.addGraph(graph2);
    
    
        // third graph
    var graph3 = new AmCharts.AmGraph();
    graph3.type = "column";
    graph3.title = "Expenses";
    graph3.valueField = "a";
    graph3.balloonText = "Expenses:[[value]]";
    graph3.lineAlpha = 0;
    graph3.fillColors = "#43acd8";
    graph3.fillAlphas = 1;
    chart.addGraph(graph3);

    // LEGEND
    var legend = new...