I made the graph based on this article plus some manual calculations for the sequel trilogy, using just scenes where a saber was active. I don’t have any idea about TROS though, if anyone would like to contribute a count for that one it would be most appreciated. 😃
Incidentally, the graph inversely correlates with my opinion of the films. A lightsaber percentage of 4 indicates a classic, 5 is acceptable, 6 is perhaps salvageable via fanedit, and anything above that is unsalvageable.