tip of the iceberg vs uncritical

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. 

uncritical

adj
  • Lacking critique or critical examination; undiscriminating. 

  • Slow to criticize. 

  • Having a disregard for critical standards or procedures. 

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