Joinpoint regression model fitted to Florida time series of proportion of prostate cancer late-stage cases. Annual proportions of prostate cancer late-stage cases were computed for non-Hispanic white and black males 65 years and over that were diagnosed over the period 1981-2007 within Florida. For both races, the segmented regression model (solid line) includes two joinpoints. Table 2 lists the estimate and 95% confidence intervals of the annual percent change (APC) for each segment, as well as the average annual percent change (AAPC) computed for the entire time period. Although the two curves are statistically non coincident, the hypothesis of parallelism of the two joinpoint regression models was not rejected at α = 0.05.