Text vertical align middle to the center of a div block

<div style="display: table; height: 300px; width: 300px; background: #aaa; _position: relative; overflow: hidden;">

<div style=" _position: absolute; _top: 50%; display: table-cell; vertical-align: middle;">

<p style=" _position: relative; _top: -50%">Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Etiam tincidunt, sapien sit amet semper molestie, diam justo ullamcorper tortor, at aliquam neque est eget lacus. Etiam sit amet odio. Maecenas vulputate malesuada lectus. Morbate malesuada lectus. Morbate malesuada lectus. Morbate malesuada lectus. Morbate malesuada lectus. Morbi vestibulum.</p>

</div>

</div>