Prostate tumors were identified using International Classification of Diseases for Oncology version 3 code 619. I classified cases by stage at diagnosis using the derived American Joint Committee on Cancer summary stage variable: early (T1 or T2), late (T3 or T4), or unknown. I grouped patients into 3 age categories (30-64 years, 65-74 years, and 75 years and older). I calculated incidence rates per 100 000 persons, standardized within age categories by age (in 5-year age groups), race (white, black, American Indian, or other), and ethnicity (Hispanic or not Hispanic) to the 2009 population. I used an unpaired t test for proportions to assess the significance of differences in rates between years. The data were analyzed in Stata version 11 (StataCorp) statistical software.