Using Google N-grams to evaluate Palpatine's many roles

Throughout the Star Wars saga, Palpatine has been a senator, chancellor, emperor, and Sith lord. So, we were curious - which one of his many political roles has gained him the most notoriety amongst Star Wars fans? Thanks the power of Google N-grams Viewer, we can observe how references to Palpatine have changed over time.

Of course, in the film version of Return of the Jedi, we only knew the character as the Emperor. As such, in books Palpatine was only referred to as "the Emperor" until the late 1980s. After Timothy Zahn's Heir to the Empire trilogy were published in the early 1990s, fans became more familiar with the Emperor's actual name and started to refer to him as Emperor Palpatine.