TIOBE Index declined 1.12% between January 2010 and January 2011. The TIOBE Index is calculated based on the number of search engine results for a particular language. Specifically, the phrase +"
Python saw the biggest growth, with +1.81% in 2010. Of the top 20 languages, PHP declined the most with a 2.24% drop.
Other notable results:
Lisp improved its ranking by +0.53%, Assembly improved by +0.86% and Pascal by +0.29%.
On the subject of Python, TIOBE wrote:
Python has become the "de facto" standard in system scripting (being a successor of Perl in this), but it is used for much more different types of application areas nowadays. Python is for instance very popular among web developers, especially in combination with the Django framework. Since Python is easy to learn, more and more universities are using Python to teach programming languages.
What do you think of TIOBE's methodology?