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The data series from Usoskin et al. (2003) (blue line) and Schove (1955) (points). The dashed line is the prediction of Schove for sunspot maxima #19 to #24. The vertical red lines indicate the transitions to Grand Minima, as determined by us (reviewed in De Jager & Duhau (2010) from the Nagovitsyn’s (2007) time series). The blue vertical line marks the transition to the Oort Grand Minimum. It was determined here in a similar way as the other transitions (vertical red lines). Letters D mark short (Dalton-type) minima. The black horizontal line is the Transition Point level and the two green vertical lines labelled 919 and 1935 mark the years in which the Hallstatt cycle passes through zero (cf. Fig. 9).