How to style element width % using ng-style

Question

I want to style my progress bar using with percentages but following ng documentation I can't seem to grasp it. It should be 20% with, but it's 100% (default).

Fiddle: http://jsfiddle.net/u6xp8csh/

Here is what I have tried

HTML

<div data-ng-app>
    <div data-ng-controller="ProgressBarController">
        <div class="progress-bar-container">
            <div class="progress-bar" ng-style="{'width' : '{{ progress }}'% }">{{ progress }}</div>
        </div>
    </div>
</div>

JS

function ProgressBarController($scope) {
    $scope.progress = 20;
}

CSS

.progress-bar-container {
    width: 300px;
    height: 100px;
    box-sizing: border-box;
    border: 1px solid black;
}
.progress-bar {
    height: 100px;
    background-color: green;
}

Answer 1

progress field accessible without '{{':

 ng-style="{'width' : progress + '%' }"

http://jsfiddle.net/gc343w7x/