This survey makes sense, honestly. The more popular characters are also the oldest and the nostalgia factor is the main reason that graph looks like that. And, they're also the characters with the greatest name recognition.
And despite how popular TFA's new characters seem right now, they still have only appeared in just one movie from two years ago. Others have been around for 40 years and many movies.
As much as I like Rey, Poe and Finn, they have a long way to go before I name them my favorites of the entire saga, I mean, come on. Leia, Luke , Solo, Vader and Obi-Wan are still by far my favorites. And Lando.