Top panel: the upper line shows the total observed sunspot area and the lower line shows the total umbra area smoothed over three month periods and corrected for foreshortening effects. Only sunspots within 60° of the centre of the disk were used to minimise errors from this correction. Bottom panel: the ratio of total umbral area to total sunspot area. This ratio is fairly constant, with the umbral area consiting of 30−40% of the total sunspot area and does not vary rapidly throughout the cycle. The errors are shown by the shaded area and are lower between 1999 and 2005 due to the increased number of sunspots at that time.