The monthly sunspot index shows a continuous decay since July (Provisional values for July: 169.1, August: 130.5, September: 109.9). Meanwhile, different prediction methods are disagreeing whether the cycle 23 is still rising or not. All this suggest that we are now very near the solar maximum.
The SIDC is the official source and World Data Center (WDC) for the international Sunspot index Ri. This index is a good measure for the solar activity and has a very long historical record. On this site you'll find the most recent sunspot index values as well as a historical database.
