jQuery Sparkline Bar Chart Labels with named offsets

HTML

<script src="http://omnipotent.net/jquery.sparkline/2.1/jquery.sparkline.js"></script>
<p>
Sparkline appears here: <span id="sparkline">&nbsp;</span>
</p>

JavaScript

// jsfiddle configured to load jQuery Sparkline 2.1
// http://omnipotent.net/jquery.sparkline/
// Values to render
var values = [100.00,100.00,100.00,80.00,80.00,66.67];

// Draw a sparkline for the #sparkline element
$('#sparkline').sparkline(values, {
    type: "bar",
    height: 50,
    width: 500,
    // Map the offset in the list of values to a name to use in the tooltip
    tooltipFormat: '{{offset:offset}} {{value}}',
    tooltipValueLookups: {
        'offset': {
            0: 'Jul',
            1: 'Aug',
            2: 'Sep',
            3: 'Oct',
            4: 'Nov',
            5: 'Dev',
        }
    },
});