Dataset Open Access
This dataset contains a single very long daily time series of sunspot numbers from 1818-01-08 to 2020-05-31.
The original dataset contains missing values and they were replaced by carrying forward the corresponding last observations (LOCF method).
Sunspot, 2015. Sunspot number version 2.0: new data and conventions. URL http://www.sidc.be/silso/newdataset