Fun quiz, but I think definitely needs more caveats/explanations about the source (the fact that the list comes from literature, etc.) Also maybe I'm just reading it wrong, but doesn't the source say the top three words (regardless of letter) are "a", "about", and "after"?
Agree some more guidance would be appreciated. E.g. I wasn't sure if verbs were only included as infinitives or conjugated, and (if conjugated) I suspect verbal Vs literature have different mix of tenses.
I'm very suspicious of a source that says "an" is used twice as much as "a," and both combined are used less than "which." Sources like the Oxford English Corpus and the Corpus of Contemporary American English both put "a" firmly in the top ten most-used words; there's no way it should be all the way down at 85.
a is 85th
about is 71st
after is 96th
The most common word is "the", accounting for over 5% of all words!