How can I show more than 15 themes at a time in the admin menu?

I have a lot of themes in my test wordpress site. I get a little frustrated that I can’t show more than 15 at a time.

Picture.png http://img820.imageshack.us/img820/5982/picturef.png

In pages and posts you can click “screen options” to choose the number, but it looks like “Themes” has no such option.

Picture-1.jpg http://img853.imageshack.us/img853/9582/picture1bbg.jpg

Is there another way to increase the number?