I'm glad that Perl job openings in the enterprise are trending upwards. But, what does the number of openings really tell us about the comparative penetration of each language? Well, a lot less than you might think.
The big difference is how many developers of language X are needed to support a given set of features. And, as every good Perl developer knows, Perl requires a lot less developers than Java.
A LOT LESS.
In the past, I was a Perl contractor for some of the largest Fortune 500 companies in the world. Every one of these companies had significant investment in both Perl and Java. A few times, I saw a given application developed in Perl, then reimplemented in Java. I distinctly remember two specific cases where this happened.
Both cases followed the same pattern. First, the Perl app was developed part-time by 2-3 developers over a couple weeks and supported by them in their "spare time" - in addition to their fulltime responsibilities. Management found out about the app and, in both cases, ordered it reimplemented in Java. Six months later, the group 20+ developers and 2-3 project managers released their first version. Unusably buggy, it had less than half the features than the prototype app in Perl. After another year (roughly 40 man-years sunk), the users in both cases got the original app up and running via back-channels and went about their work. In one case, management supported the Perl app. In the other, I think the Java app is still up and running. Maybe (6+ years later), it's finally where the original prototype was. Probably not.
The point is that a team of 3-5 Perl developers can do more than 30 Java developers. 10:1 sounds about right. Perl has already penetrated the enterprise. Frankly, the enterprise cannot exist without Perl. The enterprise just doesn't need as many Perl developers to do the same work. Think about that.