Energimyndigheten: "Energiläget i siffror 2021_0205" table 6.2 (for 1970-2019 data) Table 6.15 (Biomass 1990-2019) Biomass 1983-1989 is produced from a linear regression of table 8.1 which shows biomass energy used in electricity generation, but not the electricity produced. Therefore the same efficiency is assumed as the time period 1990-2009. Fossil is the production from thermal that is not from biomass. Therefore any biomass used before 1983 will be included in fossil. Important to note that Energimyndigheten counts peat as fossil.

https://www.energimyndigheten.se/nyhetsarkiv/2021/okning-av-fornybar-elproduktion-under-2020/ (for 2020 data)

SCB: Statistiska översiktstabeller 1950 and Statistisk årsbok from multiple years (thermal power and hydro 1913-1969) Data for 1913-1935 only gives a total for years 1913,1921 and 1931. In order to segregate the data into hydro and heat: Kander, Astrid "Economic growth, energy consumption and CO2 emissions in Sweden 1800-2000" page 59 [in turn citing Hjulström, F. (1940) Sveriges elektrifiering] the values of 30% steam 1913, 25% steam 1921 and 1931. From that rough data linear interpolations were used.