Results of age inversion for several surveys. The solid red line is the computed underlying age distribution with 68- (dark shading) and 95 (light shading) percent confidence intervals. Input log(age) PDFs for five parts of each survey are plotted with grey lines and the black dashed line shows the log(age) PDF inferred from the inversion result. The inset in each panel shows the cross-validation curves (red) and piecewise-linear fit (blue) for one part of the survey (see Sect. 3.3 for the description of the cross-validation curve).