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Table 5 Probabilities of a SXR flare \(\ge\) X100 for next 30-, 50-, and 100-year periods for 80-, 100-, 120-, and 138-year data sets in the DH and MA20 catalogues

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

Data length Occurrence probability of sunspot area \(\ge\) X100 calculated using the DHO catalog Occurrence probability of sunspot area \(\ge\) X100 calculated using the MA30 catalog
30 years 50 years 100 years 30 years 50 years 100 years
80 years (1879–1958) 0.92 0.99 1.00 0.92 0.99 1.00
100 years (1879–1978) 0.85 0.96 1.00 0.85 0.96 1.00
120 years (1879–1998) 0.73 0.89 0.99 0.74 0.90 0.99
138 years (1879–2016) 0.70 0.87 0.98 0.76 0.91 0.99