I first typed in "elf. " The result was not at all what I expected.
The highest usage was at 1800 and drops off dramtically from there.
"Vampire" on the other hand, explodes from 1980 to present.
"Zombie" has a blip at 1800, nearly disapears from about 1810 to 1930, has a small jump around 1940, cools off and then skyrockets from about 1965.
Very interesting stuff. Might be a great marketing tool, if one had the savy to know what to search for.