DC.js - Scatter Plot Not Updating

HTML

<script src="http://nickqizhu.github.io/dc.js/js/dc.js"></script>
<script src="http://nickqizhu.github.io/dc.js/js/crossfilter.js"></script>
<link rel="stylesheet" href="http://nickqizhu.github.io/dc.js/css/dc.css">
<div id="dc-timeofday-chart" />

JavaScript

var chartExample = {
    initChart: function (data) {
        data.forEach(function (e) {
            var parseDateTime = d3.time.format("%Y-%m-%dT%I:%M:%S.%LZ");
            var parseDay = d3.time.format("%Y-%m-%d");
            e.datetime = parseDateTime.parse(e.datetime);
            e.hour = d3.time.hour(e.datetime);
            e.day = d3.time.day(e.datetime);
            e.month = d3.time.month(e.datetime);
        });
        var dateRange = d3.extent(data, function(d){return d.day});
        var numberOfDays =  Math.floor((dateRange[1] - dateRange[0]) / 86400000) + 1;

        var crossfilterData = crossfilter(data);

        var timeOfDayChart = dc.lineChart("#dc-timeofday-chart");

        var volumeByHour = crossfilterData.dimension(function (d) {
            return d.datetime ? (d.datetime.getHours()):null;
        });
        var volumeByHourGroup = volumeByHour.group().reduce(
            function (p, v) {
                ++p.count;
                p.avgCount = p.count / numberOfDays;
                return p;
            },

            function (p, v) {
                --p.count;
                p.avgCount = p.count / numberOfDays;
                return p;
            },

            function () {
                return {
                    count: 0,
                    avgCount: 0
                };
            });

        timeOfDayChart.width(350)
            .height(225)
            .dimension(volumeByHour)
            .group(volumeByHourGroup)
            .x(d3.scale.linear().domain([0, 24]))       
            .valueAccessor(function(d){return d.value.avgCount})
            .xAxis()
            .tickValues([0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23])
            .tickFormat(function(d)
                        {
                            if(d == 0) return "Midnight";
                            else if(d == 7) return "8am"
                            else if (d ==11) return "noon";
                            else if...