Sources of historical statistics

Details of online sources of historical statistics across all subject areas other than the economy. These sources are either long-term time series or snapshots of a range of data from a specific point in the past.They allow comparisons between the present day and the start of data collection and any intervening period and give an understanding of patterns -have trends been smooth, random, cyclical etc? Snapshots cover a wider range of data and help us make more general comparisons between ‘then’ and ‘now’.
Most of the series go back to around the 1920s or earlier. . This note does not include links to economic data or anything to do with family history.