I don't think these results correlate at all to the popularity of a given programming language in use in the field.
For instance, pretty much ever since the language's ascendance to popularity, a visit to the bookstore will yield a veritable WALL of Java books, most of them bound for obsolescence within a year, or two, max. Sure, this happens with other programming languages too, but the constant churn of frameworks, libraries and infrastructure that happens in the Java world is a boon for book publishers.
For instance, pretty much ever since the language's ascendance to popularity, a visit to the bookstore will yield a veritable WALL of Java books, most of them bound for obsolescence within a year, or two, max. Sure, this happens with other programming languages too, but the constant churn of frameworks, libraries and infrastructure that happens in the Java world is a boon for book publishers.