3010 20170106113523.0 10.1007/s11207-016-0982-2 DOI SCART-2017-0006 Vaquero, J. M. A Revised Collection of Sunspot Group Numbers 2016 Sunspot Workshops We describe a revised collection of the number of sunspot groups from 1610 to the present. This new collection is based on the work of Hoyt and Schatten ( Solar Phys. 179, 189, 1998). The main changes are the elimination of a considerable number of observations during the Maunder Minimum (hereafter, MM) and the inclusion of several long series of observations. Numerous minor changes are also described. Moreover, we have calculated the active-day percentage during the MM from this new collection as a reliable index of the solar activity. Thus, the level of solar activity obtained in this work is greater than the level obtained using the original Hoyt and Schatten data, although it remains compatible with a grand minimum of solar activity. The new collection is available in digital format. STCE Sunspots statistics Solar cycle observations Svalgaard, L. Carrasco, V. M. S. Clette, F. Lefèvre, L. Gallego, M. C. Arlt, R. Aparicio, A. J. P. Richard, J.-G. Howe, R. Solar Physics 291 2016 9-10 3061-3074 laure.lefevre@observatoire.be published in REFERD