The datafile is on one CD-ROM disc.
Documentation is on the disc.
Because the design of the survey utilized multistage probability sampling, weights must be applied to sampled cases in order to produce national estimates. Annual changes, referred to as addenda, may include assignment of new diagnostic and procedure codes, fourth and fifth digit expansion of codes, as well as code deletions. Addendum changes go into effect each October 1. Because of possible coding changes, estimates for some codes may show discontinuity across years.