sun's rays vs sunlight

sun's rays

sunlight

verb
  • To work on the side (at a secondary job) during the daytime. 

noun
  • All the electromagnetic radiation given off by the Sun, especially that in the visible spectrum that bathes the Earth. 

  • Brightness, hope; a positive outlook. 

  • Synonym of sunrise. 

How often have the words sun's rays and sunlight occurred in a corpus of books? (source: Google Ngram Viewer )