chromium/third_party/blink/web_tests/svg/custom/percentage-rect.svg

<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
    <rect height="100" width="100" fill="red"/>
	<rect height="16.667%" width="13%" fill="green"/>
</svg>