careful vs tip of the iceberg

careful

adj
  • Conscientious and painstaking; meticulous. 

  • Taking care; attentive to potential danger, error or harm; cautious. 

tip of the iceberg

noun
  • A small indication of a larger possibility; the first part encountered of a problem that is much bigger than it seems. 

How often have the words careful and tip of the iceberg occurred in a corpus of books? (source: Google Ngram Viewer )