overalls vs skirt suit

overalls

noun
  • A loose-fitting garment worn over regular clothes to protect them. 

  • Trousers traditionally worn by cavalry. 

  • Loose-fitting pants with supporting cross-straps and a panel of material in the chest (called a bib), often associated with farm work. 

skirt suit

noun
  • A women's suit consisting of a jacket and a matching skirt 

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