Excavating the TIOBE Index

The TIOBE Index website is refreshed every month, presenting the latest headlines, updated Top 20 and Top 50 tables and an alphabetical list of the 50 languages at the bottom of the heap. For this article I wanted to use data, augmented by information from to PLDB to shed light on why some languages that originated over 30 years ago are still going strong in 2025 so the fact that when you visit the TIOBE Index you only find the current month's data there presented a problem.

This was overcome by recourse to the  Wayback Machine, the Internet Archive which enables us to view data that has long since disappeared from the web. The resource was initiated in August 2001 and so the TIOBE Top 20 for July 2001 was available. 

Using its symbols regarding change in the index - yellow equals for no change, and arrows for the number of places moved up (green) or down (red) it has been possible to reconstruct the original Top 20 positions.

While a language is in the Top 20 you can view a chart of its entire history showing its percentage rating for every month - here's the one for Lisp dating from the October 2020 edition of the TIOBE index when Lisp was about the depart the Top 20.

Such charts also gives information on its highest and lowest ever ranking. Using the Wayback Machine it has been possible to fill in information that would otherwise be missing from the table

The Wayback Machine also lets us view early versions of the familair TIOBE Top 10 chart. 

This one is for March 2007, by which time Python has risen to #8 and Ruby had just entered the top 10, while Delphi had left it. Here is is used to confirm which 20th century languages were included in the original Top 10.

Test of Time Ranking

The table below, which is sorted on the TIOBE ranking for June 2001, which is taken to be its starting point uses the data mined from the TIOBE Index together with additional data from the PDLB to address the question of why such a high proportion of the languages in the Top 20 of the TIOBE index of March 2025 date from before the millenium.