swim briefs vs two-piece

swim briefs

noun
  • A briefs-style male swimsuit such as those worn in competitive swimming, diving, and water polo. 

two-piece

noun
  • A garment consisting of two separate parts; especially such a swimsuit 

adj
  • comprising two pieces 

How often have the words swim briefs and two-piece occurred in a corpus of books? (source: Google Ngram Viewer )