modern-day vs today's

modern-day

adj
  • Current; of the present. 

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

today's

adj
  • Relating to, or produced today. 

  • Relating to, or produced in, the current historical period. 

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