Não pude encontrar do código para não exibir os anos.

<canvas width="600" height="400"></canvas>

<script>

    function drawRectangle(x, y, width, height, color) {
        var canvas = document.querySelector("canvas");
        var brush = canvas.getContext("2d");

        brush.fillStyle = color;
        brush.fillRect(x, y, width, height);
        brush.strokeStyle = "black";
        brush.strokeRect(x, y, width, height);

    }

    function drawText(x, y, text) {
        var canvas = document.querySelector("canvas");
        var brush = canvas.getContext("2d");

        brush.font = "15px Georgia";
        brush.fillStyle = "black";
        brush.fillText(text, x, y); 
    }

    function drawBar(x, y, series, colors, text) {


        var calculator = 0;

        for(var i = 0; i < series.length; i++) {
            var width = series[i];
            drawRectangle(x, y + calculator, 50, width, colors[i]);
            calculator = calculator + width;
        }

    }    

    var colors = ["blue", "green", "yellow", "red"];
    var series2015 = [50, 25, 20, 5];
    var series2016 = [65, 20, 13, 2];

    drawBar(20, 70, series2015, colors, "2015");
    drawBar(100, 70, series2016, colors, "2016");

</script>