Latitudinal distribution of sunspots for several years during cycles 19 (upper left), 21 (upper right), 16 (middle and lower left), and 14 (middle and lower right). The black curves are for the years when the mean latitude of the sunspots was between 13° and 15°. The colors of the other curves indicate the year relative to this reference year (see legend in the top right panel). The curves were smoothed with a 3 degree boxcar filter. The late phases of cycles 14 and 16 are shown separately (bottom panels) to avoid overcrowding of lines.