Probability distribution functions (PDF) for (a) umbral field strength and sunspot area, (b) sunspot area and (c) umbral field strength. Dashed lines in panels (b) and (c) delineate two components contributing to each histogram. Vertical and horizontal dashed lines in panel (a) indicate approximate division between two components (small/weak and large/strong sunspots). Overall trend in H vs. logS (panel a) agrees with equation (1). Reproduced from Nagovitsyn et al. (2017).