The report, by the Independent Office for Police Conduct, reveals that nationally there were 16 deaths in or following police custody, including one in South Yorkshire, between April 1, 2018 and March 31, 2019.
The number was down from a 10-year high of 23 in 2017/18.
There were another 63 apparent suicides following periods spent in police custody, including four in South Yorkshire, over the same period.
Nationally there were another 152 deaths following some form of ‘police contact’, such as officers being called out to investigate or deal with incidents which later resulted in a fatality.
Seven such deaths in South Yorkshire feature in the report.
There were 42 road deaths last year involving police contact in the form of police pursuits and collisions involving officers responding to emergency calls.
There were five such deaths in South Yorkshire.
IOPC Director General Michael Lockwood said: "This year we've seen a reduction in the number of deaths in or following police custody, with no deaths occurring in a police custody suite itself.
"This reflects the importance of ongoing work, to which we have contributed, to ensure police custody offers a safe as environment as possible.
"However, it is of concern that again, there is a high proportion of people dying during and immediately after custody who are vulnerable through mental health and links to drugs and alcohol."
Mr Lockwood added: "The increase in pursuit-related deaths this year points to a continued need for ongoing scrutiny of this area of policing.
"Police drivers need to be able to pursue suspects and respond quickly to emergency calls as part of their duty, but it's not without risk.
"This includes risks not only for the police and the driver of any pursued vehicle, but for passengers, bystanders and other road users.
"Pursued drivers bear responsibility for their own actions but police officers should also take into account risks to the public and only undertake a pursuit where it is safe to do so, and where authorised."
Deborah Coles, director of the charity Inquest, said: "At a time when all political parties are promising additional police on the streets, our ongoing casework shows that more police numbers are not the answer to public safety.
"Ultimately to prevent further deaths and harm, we must look beyond policing and redirect resources into community, health, welfare and specialist services."
Temporary Detective Chief Inspector Richard Hammond, from South Yorkshire Police’s Professional Standards Department, said: “We operate in accordance with strict policies and procedures and any person who comes into contact with the force, or enters custody, is treated in line with approved national practice and appropriate guidance.
“In the unfortunate event of a death occurring during or following police contact, we always evaluate the investigative findings, including those investigated independently by the IOPC, to establish if there are lessons to be learned.
“The number of road traffic incident deaths referred to the IOPC is higher than we would typically see in South Yorkshire, but this figure includes the tragic death of four people – a child and three adults - in a fatal collision in Darnall in November 2018. Three people have since been convicted and jailed in relation to this matter.
“This figure also includes a collision involving the death of a woman in Barnsley in September 2018, for which four people have been convicted and jailed. In both of these cases, a mandatory referral was made to the IOPC.”