A study of U.S. broadband access speeds suggests that the greatest changes in the market now are occurring at the top end of the market, not the lower end, even though minimum speeds are climbing.

Also, nearly all of the increase in speeds is the result of cable operator upgrades. Between 2010 and 2012, cable availability at 25 Mbps has increased 78 percent (availability grew from 43 percent of locations to 76 percent of locations).

Availability of 50 Mbps service grew 81 percent (40 percent availability to 73 percent availability).

Consumer ability to buy service at 100 Mbps or more grew 420 percent, compared to the 2010 level (8.5 percent availability grew to  to 44 percent availability).

Given that the study data ended at June 2012, one can assume continued expansion of high speed services as ISPs gear up to match Google (News - Alert) Fiber’s 1-Gbps offers. So the big story over the next few years might not be the growing minimum speeds, but the expansion of top speeds.

The NTIA study found that about 94 percent of U.S. residents can subscribe to services of at least 10 Mbps. Some 78.5 percent of U.S. residents can buy access at speeds of at least 25 Mbps.

About 37 percent can buy access at speeds between 50 Mbps (75 percent) and 100 Mbps (47 percent).

Speeds of 1 Gbps are available to about 3 percent of the population.

Though few would see mobile broadband as a full substitute for fixed access, in terms of price per bit or size of data caps, at lower speeds, mobile provides speeds and coverage quite comparable to fixed networks.

As of the middle of June 2012, 98 percent of U.S. residents could buy wired or wireless broadband at advertised download speeds of 3 Mbps or greater and upload speeds of 768 kbps or greater, the National Telecommunications and Information Administration (NTIA) reports.

About 93 percent of U.S. residents have access to advertised wired network speeds of at least

6 Mbps, NTIA says. Some 91 percent of Americans have access at 10 Mbps and 78 percent can buy access at 25 Mbps.

About 81 percent of U.S. residents have mobile access featuring download speeds of 6 Mbps or

greater.

Nearly 26 percent of the population can access fixed wireless download speeds at 6 Mbps.

Some 87 percent of the population has access to broadband from a cable operator, 74 percent have digital subscriber line access and 20 percent have access to fiber to the premises networks.

Some 34 percent of the population has access to terrestrial fixed services at a minimum of 3 Mbps downstream, while 92 percent have access to terrestrial mobile services at this speed tier.

Cable is the primary provider of services of at least 25 Mbps or greater but less than 1 Gbps.

Between June 2010 and June 2012, national broadband availability increased at all advertised speed levels. During both years, the greatest rates of change occurred in the higher speed tiers, beginning with the 25 Mbps or greater tier.

Almost 100 percent of urban residents have access to download speeds of at least 6 Mbps, while 82 percent of rural communities have access at such speeds.

The big gap is at the higher speeds. Almost 88 percent of urban residents have access to speeds of 25 Mbps. Only 41 percent of rural residents, less than half those in urban communities, have the same access. And the disparities widen as speeds climb.