The average residential broadband speed is two and half times faster than it was in 2008 as consumers move to new superfast services, Ofcom said.
Network upgrades by internet service providers (ISPs) have also helped to boost the average fixed-line residential broadband speed to 9 megabits per second (Mbit/s), up from the 3.6Mbit/s recorded in November 2008 when the communications regulator began its speeds research.
Ofcom said the trend of increasing speeds was "gathering momentum" as consumers migrated to faster services such as Virgin Media's "up to" 60Mbit/s service and BT's Infinity 2 "up to" 76Mbit/s service.
However many consumers were also benefiting from improved speeds at little or no extra cost as a result of network upgrades by ISPs, the study found.
As of May this year, more than two-thirds (68%) of UK fixed-line residential broadband users were on packages with advertised speeds above "up to" 10Mbit/s, an increase from 48% in May last year.
The proportion of residential superfast connections - those with an advertised speed of up to 30Mbit/s - has increased to 8%, up from 5% six months previously and 2% in May last year.
And these connections are also getting faster, with average speeds increasing from 35.5Mbit/s in November last year to 35.8Mbit/s in May.
Ofcom said work by BT and Virgin Media to upgrade their networks had led to to a "noticeable overall improvement" in speeds.
Of the 12 ISP packages included in the report, Virgin Media's 100Mbit/s service was the fastest with the study finding average actual speeds of 88.3Mbit/s over a 24-hour period.
BT Infinity's 76Mbit/s service delivered the highest upload speeds of all the packages, averaging 15.6Mbit/s.
The report is the seventh by Ofcom into residential fixed-line broadband speeds and is designed to help consumers choose between ISPs.
Ofcom chief executive Ed Richards said: "Our research shows that the move to faster broadband services is gathering momentum. Consumers are benefiting from network upgrades and the launch of new superfast packages, giving them faster speeds and greater choice.
"We are continuing to work with the advertising code-writing bodies and ISPs to ensure that speeds advertised reflect actual speeds experienced, to allow consumers the ability to make informed decisions when shopping around to find the most suitable package."