erratically vs unsteadily

erratically

adv
  • In an erratic manner; unsteadily or randomly, unpredictably. 

unsteadily

adv
  • In an unsteady manner, so as to shake or falter. 

  • In an uncertain manner; with hesitation or timidity. 

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