Also available in PDF.

Also available in PDF.

Data source: For 1976/01/05 to 2011/02/02 Physikalisch Meteorologisches Observatorium Davos, World Radiation Center and for 2011/02/03 to 2012/04/20 University of Colorado Solar Radiation & Climate Experiment. Data are matched using the 2010/02/03 to 2011/02/02 period. (Last modified: 2012/04/30)

Long-Term Sunspot Numbers

Also available in PDF. Data source: SIDC - Solar Influences Data Analysis Center (Data are through April 2012, Last modified: 2012/05/01)