helter-skelter vs mix-up

helter-skelter

noun

  • Confusion or turmoil. 

  • A helical fairground slide. 

adv

  • In confused, disorderly haste. 

adj

  • Carelessly hurried and confused. 

mix-up

noun

  • A confusion, mistake, muddle or misunderstanding 

How often have the words helter-skelter and mix-up occurred in a corpus of books? (source: Google Ngram Viewer )