offspring vs youngsters

offspring

noun
  • All of a person's descendants, including further generations. 

  • An animal or plant's progeny or young. 

  • Anything produced; the result of an entity's efforts. 

  • A person's daughter(s) and/or son(s); a person's children. 

  • A process launched by another process. 

youngsters

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