modern vs modern-day

modern

adj
  • Pertaining to a current or recent time and style; not ancient. 

  • Pertaining to the modern period (c.1800 to contemporary times), particularly in academic historiography. 

noun
  • Someone who lives in modern times. 

modern-day

adj
  • Designating a present-day version of someone or something in history. 

  • Current; of the present. 

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