Trends in performance of pelvic lymphadenectomy for stage I-II endometrial cancer. Annual percent changes are: A) 1.7 (95%CI 1.4–1.9, P < 0.001), B) 5.2 between 1988 and 1999 (95%CI 3.3–7.1, P < 0.001) and 1.8 (95%CI 1.3–2.3, P < 0.001), C) 2.1 (95%CI 1.4–2.8, P < 0.001), D) 1.9 (95%CI 1.6–2.2, P < 0.001), E) 2.3 (95%CI 1.9–2.8, P < 0.001), and F) 1.9 (95%CI 1.1–2.7, P < 0.001). Bars represent mean and standard deviation. Abbreviation: CI, confidence interval.