(slang) squirting vs female ejaculation

(slang) squirting

female ejaculation

noun
  • The forceful expulsion of fluids from the vagina during the female orgasm, possibly originating from the Skene's gland (paraurethral gland) and/or urethra. 

How often have the words (slang) squirting and female ejaculation occurred in a corpus of books? (source: Google Ngram Viewer )