I'm not clear exactly what's being treated as hit-and-run here (although I do understand the requirements to stop and give details imposed by the Road Traffic Act 1988.) As well as victims left lying in the road, I suspect there are cases where a parked car is hit and the offending drivers scarpers.
Recorded hit-and-run incidents increased from 19,239 in 2013 to 28,010 in 2017, according to Freedom of Information responses from 27 of the 44 police forces in England and Wales.
The MIB handles cases which involve a pay out, so may be a better measure of the more serious cases.
The Motor Insurers' Bureau, the body that compensates victims of uninsured drivers, also said the number of victims of hit-and-runs has been rising since 2013. It now handles more than 16,000 cases a year.
There's academic research:-
Dr Matt Hopkins, from the University of Leicester, has interviewed dozens of hit-and-run drivers about why they failed to stop.
"What the research seems to be pointing to is that a fair proportion of hit-and-run collisions are related to drivers who tend not to have valid insurance, tend not to have a valid licence", he said.
I's add to that people who've had too much sherbet or are with somebody else's partner.