Introduction - If you have any usage issues, please Google them yourself
Using archival records,astronomers have applied Wolfer s rule to determine sunspot activity back to the year 1700. Today the sunspot index is measured by many astronomers and the worldwide distribution of the data is coordinated by the Solar Influences Data Center at the Royal Observatory of Belgium.
The text file sunspot.dat in the matlab/demos directory has two columns of numbers. The first column is the years from 1700 to 1987 and the second column is the average Wolfer sunspot number for each year.