unlade vs vacate

unlade

verb
  • To disburden; take the burden from; relieve. 

  • To discharge a cargo; discharge a burden. 

  • To discharge the cargo from. 

  • To unload. 

vacate

verb
  • To leave an office or position. 

  • To have a court judgement set aside; to annul. 

  • To leave an area, usually as a result of orders from public authorities in the event of a riot or natural disaster. 

  • To move out of a dwelling, either by choice or by eviction. 

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