Occurrence of variable stars in classes with at least five members against OC age. Sample restrictions have been applied to ensure consistent detectability limits for each class, cf. Appendix D. For YSOs and ECLs, an additional limit on M_G has been applied as labeled. Labels on the left abbreviate GDR3 variability classes, cf. Table B.3. The number of variables is normalized by the number of OC members with 4 ≤ M_G ≤ 5 [mag]. Dark gray error bars show Poisson uncertainties, while light gray lines show the KDE-smoothed distribution.