Also available in PDF.
Data source: For 1976/01/05 to 2003/02/28 Physikalisch Meteorologisches Observatorium Davos, World Radiation Center and for 2003/03/01 to 2015/06/24 University of Colorado Solar Radiation & Climate Experiment. Data are matched using the 2003/03/01 to 2004/02/29 period. (Last modified: 2015/07/01)
Long-Term Sunspot Numbers
Also available in PDF. Data source:WDC-SILSO, Royal Observatory of Belgium, Brussels Note from SILSO: Since July 1st 2015, the original Sunspot number data are replaced by a new entirely revised data series. On this occasion, the data are presented in a new array of files, containing additional values that were not present in the original series. For proper tracking of those changes, the present version is numbered 2.0. (Data are through June 2015, Last modified: 2015/07/01)