I am using D3 and want to add the greek letter delta. 

This is in the tag of my HTML:

```
<meta http-equiv="content-type" content="application/xhtml+xml; charset=utf-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">

```

This is where the problem lies:
'bars' is a variable that stores a selection of class '.bar' and appends 'g' to them. 

```
var text = bars.append('text')
            .attr('class', 'delta')
            .text(function(d) {
                // Rounding to one decimal place
                var delta = Math.abs(d.benchmark - d.completes);
                return Math.round(delta * 10) / 10 + "%";
            })
            .attr('x', 0)
            .attr('dy', '-0.25em')
            .attr('style', 'text-anchor: left; vertical-align: center')
            ;

```

In this particular line I get problems:

```
return Math.round(delta * 10) / 10 + "%";

```

Things I have tried:

```
return Math.round(delta * 10) / 10 + "%Δ"; //Displays ? instead of Δ
return Math.round(delta * 10) / 10 + "%&Delta;" // Displays the string literal &Delta;
return Math.round(delta * 10) / 10 + "%&#916;;" // Displays the string literal &#916;

```

Not really sure how to proceed. If it matters, the font is sans-serif

I am not very familiar with SVG text but all I want to do is write the greek letter delta.