Take a look at:
http://www.google.com/trends?q=python%2C+perl%2C+ruby&ct...
vs
http://www.google.com/trends?q=cpan%2C+pypi%2C+rubyforge&...
Google Trends isn't a great measurement tool, but the 3 languages have similar search volumes (with Perl declining, Python stable and Ruby ascending), yet CPAN is has a much higher volume than either RubyForge and PyPI. I think the relevance of each repository to its language community isn't comparable.
That's my only point. Dynamic languages are growing in popularity, and Perl is among them. And, if Perl doesn't grow as fast as Ruby and Python, that's fine, too. It'll still be a few years before Python and Ruby catch up to Perl in usage and lines of code and number of projects. (And none of them will ever catch up to PHP. JavaScript might, though.)
Checkout these two instead....
http://www.google.com/trends?q=python+scripting%2C+perl+scri...
http://www.google.com/trends?q=python+programming%2C+perl+pr...
In fact all languages have declined. Which isn't surprising because Google Trends is just showing you the frequency of these search terms used over time.
There is a lot more things to search for now on the web compared to 2004!