Broadband speeds on average are within 80 percent of what major Internet service providers advertise, a big improvement from two years ago, according to a government study.

The Federal Communications Commission studied cable, DSL and fiber-to-the-home services at 13 top U.S. broadband providers.

The agency found Verizon Communications Inc's fiber network was best at meeting or exceeding advertised maximum download speeds, while Cablevision Systems Corp was the worst.

Overall, the numbers were a big boost from 2009, when data indicated download speeds were often about half of Internet service providers' (ISP) maximum advertised speeds.

Most major ISPs are providing service close to what they're advertising. This represents a significant improvement over the findings from two years ago when we first shined a light on this issue, FCC Chairman Julius Genachowski said, unveiling the study's findings at a Best Buy Co store in the District of Columbia.

During peak consumer usage hours when networks are busiest, actual download speeds varied from 114 percent to 54 percent of advertised speed among the different ISPs, the FCC said.

The report comes as the FCC is promoting its National Broadband Plan, unveiled last year. It is a blueprint for expanding coverage, making more airwaves available for mobile services and upgrading Internet speeds up to 25 times recent averages.

The complete findings of the report, its raw data and an FCC-prepared guide for consumers will be made available online. The FCC says the data will help consumers decide which Internet speed, service and provider best meet their needs.

This report pretty well dispels the myth ... that there's a huge gap between advertised and actual speeds, and in fact we do pretty well here in the United States, said Richard Bennett, a senior fellow at the Information Technology and Innovation Foundation.

Not everyone was impressed with the study's findings.

This study indicates Comcast, Cox and Verizon FiOS largely perform well, but other companies like Cablevision, AT&T, MediaCom and Frontier all fail to deliver their customers the quality of service promised, said S. Derek Turner, research director for the public interest group Free Press.

Free Press said ISPs should be held to the same standard as other industries, where giving customers less than what they pay for is a serious offense.

The 13 participating ISPs in the new study included Verizon, which had its fiber and DSL services tested separately, AT&T Inc, Comcast Corp, Time Warner Cable Inc, Cox Communications, Cablevision, Frontier Communications Corp, CenturyLink Inc, Charter Communications Inc, Insight Communications Co, Mediacom Communications, Qwest Communications and Windstream Corp.

(Reporting by Jasmin Melvin; editing by John Wallace)