I'm doing some research for a project and I'm trying to find out what are the 5 most-used server-side languages.

I found this chart (http://i.stack.imgur.com/vPXgR.jpg) on css-tricks.com (produced from a poll the site owner ran), but in the comments, some suggested that the poll may be skewed in favor of php because most of the site visitors are designers.

I'm not sure if this chart looks realistic. Does anyone know of similar stats?