Adding Data Dynamically to a Column in Highcharts - highcharts

Question

I'm attempting to create a column chart that can be updated by clicking on a button, so that users can track their progress through a quiz. I'm very close with this fiddle, but my logic is off, because although the column data increases after each click, the y axis is also adding the data from the previous clicks into the sum of the column data: eg. click on button A, column A receives 1 point, Click on button B, Column B receives one point, but adds on the column A point for a total of 2 in column B, rather than just getting one point.
https://jsfiddle.net/mrjarbenne/17en2sc8/
var chart = Highcharts.chart('container', {
chart: {
type: 'column'
},
xAxis: {
categories: ['A', 'B', 'C']
},
series: [{
data: [0, 0, 0]
}]
});
// button handler
var y = 0;
$('#button').click(function () {
y += 1;
chart.series[0].data[0].update(y);
});
// button handler
var y = 0;
$('#button2').click(function () {
y += 1;
chart.series[0].data[1].update(y);
});
// button handler
var y = 0;
$('#button3').click(function () {
y += 1;
chart.series[0].data[2].update(y);
});
This other fiddle is another method I've been trying to work with, but I'm struggling to remove the Realtime functionality so it's just a stand-alone element (I don't want the chart to be updated by multi individuals in a session)
http://jsfiddle.net/realtimeframework/xdo4daju/
Thank you for any direction you can provide on where I'm going wrong.