Its usage has increased, but so has the usage of other languages. Its drop in popularity is relative to its share of all users. If Alice has two apples and Bo

Its usage has increased, but so has the usage of other languages. Its drop in popularity is relative to its share of all users. If Alice has two apples and Bob has three apples, Bob has 60% of the apples. But if Alice gets four more apples and Bob only gets one, Bob has only 40% of the apples, despite having more than he did before. It's the same with TIOBE's popularity index.