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Table 4 Probabilities of a sunspot group with area \(\ge\) 6000 MSH for next 30-, 50-, and 100-year periods for 80-, 100-, 120-, and 138-year data sets in the DHO and MA20 catalogues

From: Extremely large flares/multiple large flares expected from sunspot groups with large area

Data length Occurrence probability of sunspot area \(\ge\) 6000 MSH calculated using the DHO catalog Occurrence probability of sunspot area \(\ge\) 6000 MSH calculated using the MA30 catalog
30 years 50 years 100 years 30 years 50 years 100 years
80 years (1879–1958) 0.89 0.97 1.00 0.89 0.97 1.00
100 years (1879–1978) 0.82 0.94 1.00 0.82 0.94 1.00
120 years (1879–1998) 0.66 0.84 0.97 0.75 0.90 0.99
138 years (1879–2016) 0.62 0.80 0.96 0.72 0.88 0.99