ChartJS - Line Chart - Y axis scale problem ?

Line Chart - Y axis scale problem ?

HTML

<script src="http://www.chartjs.org/assets/Chart.js"></script>
<body>
    <h3>Working Chart</h3>
    <canvas id="canvas" height="450" width="600"></canvas>
</body>

CSS

canvas { background-color : #eee;
}

JavaScript

var lineChartData = {"datasets":[{"data":["6.0","6.0","9.0","9.0","8.4","8.5","8.57","7.5","7.3","9.3","9.0","10.0","9.23","8.57"]}],"labels":["Sprint 1","Sprint 2","Sprint 3","Sprint 4","Sprint 5","Sprint 6","2014: Sprint 1","2014: Sprint 2","2014: Sprint 3","2014: Sprint 4","2015: Sprint 5","2015: Sprint 6","2015: Sprint 7","2015: Sprint 8"]};

var myLine = new Chart(document.getElementById("canvas").getContext("2d")).Line(lineChartData);