The wide variation in epidural and cesarean delivery rates in Israeli hospitals makes annual delivery numbers a poor assessment of obstetric anesthesia activity. For each composite figure, the upper portion consists of annual numbers of deliveries, epidurals, and cesareans. The lower portion represents the calculated OAAI. Ranking of hospital activity by annual delivery numbers alone does not reflect the ranking by OAAI. Data for 2005 (upper) and 2007 (lower).