an vs throughout

an

prep
  • In each; to or for each; per. 

article
  • Used before one and words with initial u, eu. 

  • Used before a vowel sound. 

  • Used before all consonants. 

  • Used before /h/ in an unstressed syllable. 

  • Used before /h/ in a stressed syllable. 

num
  • one 

noun
  • The first letter of the Georgian alphabet, ა (Mkhedruli), Ⴀ (Asomtavruli) or ⴀ (Nuskhuri). 

throughout

prep
  • In every part of; all through. 

adv
  • In every part; everywhere. 

  • During an entire period of time, the whole time. 

How often have the words an and throughout occurred in a corpus of books? (source: Google Ngram Viewer )