It is difficult to determine which programming languages are most widely used, and what usage means varies by context. One language may occupy the greater number of programmer hours, a different one have more lines of code, and a third utilize the most CPU time. Some languages are very popular for particular kinds of applications. For example, COBOL is still strong in the corporate data center, often on large mainframes; FORTRAN in engineering applications; C in embedded applications and operating systems; and other languages are regularly used to write many different kinds of applications.
Various methods of measuring language popularity, each subject to a different bias over what is measured, have been proposed:
One organization tracking the popularity of programming languages is Tiobe. Their monthly Programming Community Index has been published since 2001, and shows the top 10 languages' popularity graphically, the top 20 languages with a rating and delta, and the top 50 languages' ratings.[6] The numbers are based on searching the Web with certain phrases that include language names and counting the numbers of hits returned.
Combining and averaging information from various internet sites, langpop.com claims that [7] in 2008 the 10 most cited programming languages are (in alphabetical order): C, C++, C#, Java, JavaScript, Perl, PHP, Python, Ruby, and SQL.
The Language Popularity Index [8] is based on a similar approach, however in a totally transparent way: counts for all {search engine, language} pairs are published. An Open Source tool for grabbing counts from search engines is provided as well, so the rankings can be reproduced and verified.
The web site Programming Language Popularity aggregates statistics and charts on language popularity across a number of methodologies.[7]