percentFormatString: String

Defines how percent values are formatted before they appear on the indexLabel or toolTip. You can format percent values using this property.

• You can read more about the supported formatting options here.

var chart = new CanvasJS.Chart("chartContainer", 
{
.
.
Data: [{
percentFormatString: "#0.##",
.
.
},
]
});
Chart.render();
}