The Department publishes annual figures covering additional housing for social rent (table 1006) and affordable rent (table 1006b) by local authority area. These tables can be used to estimate the delivery of social housing and can be found here: https://www.gov.uk/government/statistical-data-sets/live-tables-on-affordable-housing-supply These data include delivery by both local authorities (council housing) and by private registered providers (housing associations). They include both new built and acquired social housing.