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Comparison of the original Hoyt & Schatten (1998a, 1998b) GSN with the SN* series of Clette & Lefèvre (2016), the backbone-based group sunspot number (RGS) of Svalgaard & Schatten (2016), and the provisional GSN* series of Cliver & Ling (2016) which corrected flaws in GSN, for 1841–1976. The three group sunspot number series are normalized to SN* over the 1916–1946 interval. Cycle numbers are given at the bottom of the figure.
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