I am not sure what to make of search trends. I compared Go with Objective C and Swift, and they are both lower than Go. That seems to mean that people are writing more Go programs than iPhone apps, and there sure are a lot of apps around these days. I am guessing there are a lot of confounding factors that lead to search volume -- go users are going to "go doc foobar", which Google does not track. Java puts the name of the programming language in nearly every error message, which people often type into Google. While these do not affect the trends (Java declining, Python increasing), they probably make it difficult to compare the raw magnitudes between languages.