oft-repeated vs soporific

oft-repeated

adj

  • repeated often or frequently 

soporific

adj

  • Boring, dull. 

  • Tending to induce sleep. 

noun

  • Something boring or dull. 

  • Something inducing sleep, especially a drug. 

How often have the words oft-repeated and soporific occurred in a corpus of books? (source: Google Ngram Viewer )