erode vs whittle

erode

verb
  • To destroy gradually by an ongoing process. 

  • To wear away by abrasion, corrosion or chemical reaction. 

whittle

verb
  • To reduce or gradually eliminate something (such as a debt). 

  • To cut or shape wood with a knife. 

  • To make eager or excited; to excite with liquor; to inebriate. 

noun
  • A knife; especially, a pocket knife, sheath knife, or clasp knife. 

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