Companies handed British drivers an average of 12,000 tickets every day during the 2020/21 financial year, analysis of Government data by the RAC Foundation indicated.
This was despite coronavirus restrictions, which saw the number of car journeys fall to as low as 22% of normal levels.
The total of 4.4 million tickets issued was down from 8.4 million during the previous 12 months.
Parking companies obtain records from the Driver and Vehicle Licensing Agency (DVLA) to chase car owners for alleged infringements in private car parks such as at shopping centres, leisure facilities and motorway service areas.
Each resultant ticket can cost drivers up to £100.
Steve Gooding, director of the RAC Foundation, told the PA news agency: "With the country and the economy in various states of lockdown, we'd have expected to see the number of keeper details being sought by the private parking sector falling quite dramatically.
"But what we have to realise is that the much-reduced number still amounts to 12,000 per day - which seems extraordinary when most of us have been following orders to stay at home and cut travel.
"Even if many of the parking charge notices issued are subsequently dropped when they are challenged, some people won't believe that challenge is a reasonable option and so they pay up rather than face the hassle. That can't be right."
Some 151 firms requested the data in 2020/21. The biggest buyer was ParkingEye with 975,559 records.
The DVLA charges private firms £2.50 per record.
The agency says its charges are set to recover the cost of providing the information and it does not make any money from the process.
The Parking (Code of Practice) Bill, introduced by Sir Greg Knight MP, became law in March 2019 with the aim of bringing rogue parking firms into line or putting them out of business.
In March, the Ministry of Housing, Communities and Local Government said it expected a code of conduct to be created before this summer, and a single appeals body to be launched by mid-2022.
Here are the number of vehicle keeper records obtained from the DVLA by parking management companies since 2006/07, according to RAC Foundation analysis:
2020/21: 4.40 million
2019/20: 8.41 million
2018/19: 6.81 million
2017/18: 5.65 million
2016/17: 4.71 million
2015/16: 3.67 million
2014/15: 3.06 million
2013/14: 2.43 million
2012/13: 1.89 million
2011/12: 1.57 million
2010/11: 1.17 million
2009/10: 1.03 million