References/Notes/Attributions:
Author(s)
R
Source
WDC-SILSO, Solar Influences Data Analysis Center (SIDC), Royal Observatory of Belgium, Av. Circulaire, 3, B-1180 BRUSSELS Currently at http://www.sidc.be/silso/datafiles
See Also
sunspot.month is a longer version of sunspots; the latter runs until 1983 and is kept fixed (for reproducibility as example dataset).