I mention this because I classify 1980 as a landslide (Reagan beat Carter by around 10%) but thanks to the third party candidate John Anderson, he didn't win 58% - he won 50.75%.
1980 was not a landslide unless you use ridiculously low criterias that make the term void.
Of course if you set your own criterias just to make sure the elections you like are called landslides, it's not surprising.
How do you not quantify 1980 as a landslide when Reagan won 44 states, 489 electoral votes, and a 10 point win in the popular vote?