First, we analyze the distribution of the occurrence frequency of sunspot-number values. The histogram for sunspot-number distribution (for the series shown in Figure 17) is shown in Figure 18. The over-decades filtered sunspot numbers range between 0 and 95. The bulk of the distribution can be roughly approximated by a normal Gaussian distribution with a mean of 31 and standard deviation of = 30. However, there are apparent excesses both at very low (SN < 10) and high (SN > 70) sunspot numbers. These excesses are very unlikely to be a result of random fluctuations or noise in the data and, as argued in Section 4.3, correspond to special states of the solar dynamo, namely, the grand minima and grand maxima. It is important that the entire distribution is more-or-less consistent with the directly-observed sunspot series after 1610, suggesting that the latter can serve as a representative sample for sunspot-activity statistics, including a grand minimum (the Maunder minimum) and the modern maximum.
This work is licensed under a Creative Commons License.