The TIOBE Programming Community index gives an indication of the popularity of programming languages. The index is updated once a month. The ratings are based on the number of skilled engineers world-wide, courses and third party vendors. The popular search engines Google, MSN, Yahoo!, and YouTube are used to calculate the ratings. Observe that the TIOBE index is not about the best programming language or the language in which most lines of code have been written.
The index can be used to check whether your programming skills are still up to date or to make a strategic decision about what programming language should be adopted when starting to build a new software system.
Since there are many questions about the way the TIOBE index is assembled, a special page is devoted to its definition.
The ratings are calculated by counting hits of the most popular search engines. The search query is executed for the regular Google, Google Blogs, MSN, Yahoo!, and YouTube web search for the last 12 months. The web site Alexa.com has been used to determine the most popular search engines.
The number of hits determine the ratings of a language. The counted hits are normalized for each search engine for the first 50 languages.
Besides the rating of programming languages, there is also a status indicated in the TIOBE chart. Programming languages that have status “A” are considered to be mainstream languages. Status “A-” and “A–” indicate that a programming language is between status “A” and “B”. If a programming language has a rating that is higher than 0.7% (yes, this number is arguable but we had to fix it somewhere) for at least 3 months it is rewarded status “A”. The first two months the programming language will receive status “A–” and “A-” respectively. The opposite holds for languages that go from status “A” to status “B”. So if a language had status “A” 2 months ago, a rating of “0.607%” last month and a rating of “0.687%” now, it will have status “A–“.
Programming languages that are very similar are grouped together. Currently the maximum of the hits of the individual languages is taken into account when calculating the ratings of groupings. In the future we will do a better job and take the union (from mathematical set theory) of all the hits.
The long term trends for the top 10 programming languages can be found in the line diagram below.
No wonder Java tops the ranking. And it will continue to hold that position for some time to come. What I am surprised to see there was Pascal is gaining popularity and people are using it nowadays. You can see the list of top 50 languages here.