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.
The long term trends for the top 10 programming languages can be found in the line diagram below.
The table below some long term trends are listed about categories of languages.