score:12

Accepted answer

I would use the Renderer.text to annotate the chart (and not do it in the legend since you have so many data points).

chart: {
    events: {
        load: function(event) {
            var total = 0; // get total of data
            for (var i = 0, len = this.series[0].yData.length; i < len; i++) {
                total += this.series[0].yData[i];
            }
            var text = this.renderer.text(
                'Total: ' + total,
                this.plotLeft,
                this.plotTop - 20
            ).attr({
                zIndex: 5
            }).add() // write it to the upper left hand corner
        }
    }
},

Fiddle example.

enter image description here

score:6

In addition to Mark's answer, to calculate the total, we do not need the for-loop statement. So, the code can be reduced.

chart: {
    events: {
        load: function(event) {
            var total = this.series[0].data[0].total;
            var text = this.renderer.text(
                'Total: ' + total,
                this.plotLeft,
                this.plotTop - 20
            ).attr({
                zIndex: 5
            }).add() // write it to the upper left hand corner
        }
    }
},

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