in round numbers vs roughly

in round numbers

roughly

adv
  • Unevenly or irregularly. 

  • Without precision or exactness; imprecisely but close to in quantity or amount; approximately. 

  • In a rough manner; without kindness, softness, or gentleness. 

How often have the words in round numbers and roughly occurred in a corpus of books? (source: Google Ngram Viewer )