chart.js supports this by defaul check the link. chartjs
you can set the label in the options attribute.
options object looks like this.
options = {
scales: {
yAxes: [
{
id: 'y-axis-1',
display: true,
position: 'left',
ticks: {
callback: function(value, index, values) {
return value + "%";
}
},
scaleLabel:{
display: true,
labelString: 'Average Personal Income',
fontColor: "#546372"
}
}
]
}
};