A crude look at my database just selecting non-blank song text lines with 1st 2 chars blank (the choruses are usually indented) or "ch" (for Ch., cho. and chorus, which sometimes appears on the 1st line of the chorus) yielded just under 36,000 lines, some of which are not actual chorus (Chorus: appears on line before the chorus text, some songs are actually indented, and probably some choruses are not indented). But even this crude assignment of lines would probably find most chorus searches before needing to check full text.

Mick