Figure 2

Concentration curves for conservative and non conservative surgery by age-group, area income and area educational level. X axis represents quintiles of the distribution of socioeconomic level; y axis represents quintiles of the distribution of rates of surgery. Solid line represents conservative surgery. Dashed line represents non conservative surgery. Explanation: the level of dominance of each concentration curve is determined by comparing it to the diagonal line of 45°. If the concentration curve is below the diagonal (concentration index >0), it is indication that surgery rates are less concentrated in the first population group (lower economic level) and more concentrated in the last population groups (higher economic level). If the concentration curve is located above the diagonal (concentration index < 0) it indicates that surgical rates are more concentrated in the first population groups (lower economic level) and less concentrated in the last population groups (higher economic level).