change the default distance in between the parallel axis in highchart

I am using the high-chart to draw the graph.

Code

Complete code is non JS_Fiddle

Highcharts.chart('container', {
    xAxis: {
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec']
    },

    series: [{
        data: [29.9, 71.5, 106.4, 129.2, 144.0, 176.0, 135.6, 148.5, 216.4, 194.1, 95.6, 54.4]
    }]

});

Graph:

Problem: Problem is that i want to change the distance in between all parallel lines from 50 to 10 as you can see in the image. You can see the code on js_fiddle. I have been search for the solution more than 5 hours. Kindly help me.