belt-tightening vs depletion

belt-tightening

noun
  • A reduction in expenditure, often as a result of financial restrictions. 

adj
  • Causing or involving a reduction in expenditure. 

depletion

noun
  • gradual expense or use of natural resources over time. 

  • The consumption of a resource faster than it can be replenished. 

  • The act of depleting, or the state of being depleted; exhaustion. 

How often have the words belt-tightening and depletion occurred in a corpus of books? (source: Google Ngram Viewer )