bikini vs one-piece

bikini

noun
  • A brief two-piece bathing suit worn by girls and women, especially one that exposes the midriff and navel. 

  • A brief bathing suit worn by men. 

one-piece

noun
  • A one-piece article of clothing, especially a swimsuit. 

adj
  • Composed of a single integral unit or so appearing. 

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