This might be the answer. It is not that the language became more popular, but rather the search keyword ada...
> This Month's Changes in the Index
> William Herrera told us that programming language ADA might have been boosted in the TIOBE index because of the Ada Lovelace architecture of NVIDIA. For this reason we have added "-NVIDIA" to Ada's search term. As a consequence, Ada dropped from position #9 last month to position #13 this month.
> This Month's Changes in the Index > William Herrera told us that programming language ADA might have been boosted in the TIOBE index because of the Ada Lovelace architecture of NVIDIA. For this reason we have added "-NVIDIA" to Ada's search term. As a consequence, Ada dropped from position #9 last month to position #13 this month.