Data collection began in 2000; the final imaging data release (DR9) covers over 35% of the sky, with photometric observations of around nearly 1 billion objects, while the survey continues to acquire spectra, having so far taken spectra of over 4 million objects. The main galaxy sample has a median redshift of "z" = 0.1; there are redshifts for luminous red galaxies as far as "z" = 0.7, and for quasars as far as "z" = 5; and the imaging survey has been involved in the detection of quasars beyond a redshift "z" = 6.