The Home Office collects and publishes data on joiners in the annual police workforce statistics, which can be found here:
In 2018/19, 9,427 police officers joined the 43 police forces in England and Wales, accounting for 8% of officers. Excluding those who transferred from other forces, joiners accounted for 6% of all officers. This was a 16% increase on the previous year and the highest number of joiners in a financial year since 2008/09.
The Government is also delivering on the people’s priorities by recruiting 20,000 additional police officers over the next three years. In October 2019 the Home Office confirmed officer allocations for every force in England and Wales in the first year of the uplift. https://www.gov.uk/government/news/home-office-announces-first-wave-of-20000-police-officer-uplift
The Home Office has announced plans to publish quarterly updates outlining the progress on delivering the police uplift programme. They will start from April 2020, lasting throughout the duration of the campaign.