The Home Office collects data from forces on the number of individuals released on pre-charge bail. The most recent statistics were published on 24 October 2019 www.gov.uk/government/statistics/police-powers-and-procedures-england-and-wales-year-ending-31-march-2019. Due to data quality issues, these statistics can give an indicative picture only, and should be treated with caution. Figures suggest 86,600 individuals were released on pre-charge bail year ending 31 March 2019.
Work is ongoing to improve this data collection, and to explore a separate but complementary collection on released under investigation.