Rebtel announces part two of a two-part survey conducted on their behalf by Harris Interactive online in September, which measured consumer sentiment on International calling services and providers.

According to the study, 1 in 4 U.S adults make international calls, and of those who spend money to make such calls, the average spend is approximately $34 every month. With an estimated 235 million U.S. adults, this works out to roughly 58.8 million Americans shelling out nearly $1.98 billion on international calls outside of the U.S. monthly and $23.8 billion annually.

For adults who make international calls, the majority do so using a landline (51%), either a traditional landline service provider (42%) and/or a VoIP service such as Vonage (12%). Another 44% make international phone calls via their mobile phones, through carrier calling rates (25%), special long distance packages (20%), and/or a VoIP service/application (9%). Another 25% of those who make international phone calls do so using their computer through software based services like Skype, while 20% use calling cards and 4% use something else.

“The international calling industry for calling from the U.S. abroad is now estimated at a $23.8 billion market,” said Andreas Bernstrom, CEO of Rebtel. “Over the next few years we believe this will shift in a dramatic way, to low cost calling solutions on mobile phones away from the landline.”

Men call Mars. Women call Venus.

Of those who make international phone calls men are more likely than women to do so via their computer through software based services like Skype (31% vs. 19% respectively).

Men are more likely than women to say that if they were going to change the way they make international phone calls they would switch to use their mobile phone VoIP service/application (10% vs. 2% respectively) or a landline (26% vs. 10% respectively).

Men are more likely than women to say they make video calls (16% vs. 11% respectively). Of men and women who do make video calls, men are also more likely than women to say that they would be willing to pay a monthly fee to be able to do so (42% vs. 24% respectively).

Ethnic breakdown: General U.S populations vs. Hispanic and Black/African American respondents

The study also took a look at two of the most heavily represented ethnic groups and found that Hispanic respondents led the way in international calls with 36% saying they make them, whereas only 26% of the Black/African American respondents said they make calls internationally.

Have a smartphone with an application for international calling:

Hispanic respondents – 14%
Black/African American respondents – 14%
U.S / General population – 8%

Make video phone calls:
Hispanic respondents – 22%
U.S / General population – 14%
Black/African American respondents – 10%

Those who make video calls would be willing to pay a monthly fee for the service
Hispanic respondents – 58%
Black/African American respondents – 37%
U.S / General population – 34%

For those who spend money to make calls, the average spent per month is:
Hispanic respondents – $46
Black/African American respondents – $35
U.S. / General population – $34

This survey was conducted online within the United States by Harris Interactive on behalf of Rebtel from September 1 – 3, 2010 among 2,258 adults ages 18 and older. This online survey is not based on a probability sample and therefore no estimate of theoretical sampling error can be calculated.