Over 20 million VoIP subscribers in the United States

These represented 13 percent of the nation's 162 million wired connections as of December 31, 2008. The overwhelming majority were residential. Only one percent of those VoIP lines served businesses.

But VoIP still represents a relatively small percentage of the total number of landline phone subscriptions. The majority are still of the traditional switched access variety, carried over copper wire systems—141 million of these, all told. They count for 87 percent of all the lines (48% residential; 39% business accounts).

The last few years?

Has VoIP use significantly expanded over the last few years? Interconnected VoIP service represents an important and rapidly growing part of the U.S. voice service market, the agency's report says.

The incumbents usually offered their VoIP via DSL or Other Wireline technology (98.1%) and the non-incumbents, mostly cable companies, provided it via coaxial lines.