employee vs worker

employee

noun
  • An individual who provides labor to a company or another person. 

  • One way to encourage your employees to work harder is by giving them incentives. 

worker

noun
  • A person who performs labor for a living, especially manual labor. 

  • A nonreproductive social insect, such as ant, bee, termite, or wasp. 

  • A female ant, bee, termite or wasp. 

  • A thread performing one instance of a particular task within a program. 

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