More U.S. drivers report talking on their cellphones behind the wheel than their counterparts in seven Europe countries, says a study released Thursday by the Centers for Disease Control and Prevention.

In a survey, nearly 69 percent of U.S. drivers said they had talked on a cellphone while driving within the previous 30 days. The share of European drivers who said they chatted on their phones ranged from 21 percent in the United Kingdom to 59 percent in Portugal.

A larger share of U.S. drivers also reported reading or sending text or email messages while driving than drivers in six of the European countries. Only Portugal’s drivers matched those in the U.S. for this distracting habit–31 percent in both countries. Spain had the smallest share of drivers who said they texted or emailed, 15 percent.

The study was based on online surveys of drivers ages 18 to 64 in the U.S., Belgium, France, Germany, the Netherlands, Portugal, Spain, and the United Kingdom in 2011.

Researchers offered no explanation for why the use of distracting mobile devices is more common in the U.S. than other countries. Mobile device markets in the U.S. and Europe are similarly saturated, making it unlikely that the findings are attributable to differing portions of the population owning devices in the countries, the study said.

It’s also unlikely that differences in local laws can fully explain why more U.S. drivers than European drivers say they use their phones, the study said. Nearly all European countries banned hand-held cellphone use by drivers, yet there was a large variation in the share of drivers reporting the use of cellphones in the seven EU countries surveyed.

In the U.S., 39 states and the District of Columbia have banned texting while driving. Ten states and the District of Columbia have banned handheld cellphone use for all drivers. But the study’s author, CDC epidemiologist Rebecca Naumann, said those laws haven’t yet proven effective in decreasing these behaviors.

The study’s finding that more than two-thirds of U.S. drivers reported cellphone use and a third had reported texting or emailing is consistent with previous studies. A national telephone survey by the AAA Foundation for Traffic Safety conducted in 2010 found that 69 percent of drivers had used a cellphone while driving and 24 percent had texted while driving during the previous 30 days. Similar estimates have been reported from surveys carried out by the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety.

“To me this says we still have a huge distracted driving problem. It’s a cultural problem, and we haven’t convinced the country yet that this is a serious issue,” said Jonathan Adkins, deputy executive director of the Governors Highway Safety Association, which represents state highway safety offices.

Researchers also looked specifically at U.S. drivers and found:

  • There were no significant differences between men and women in terms of cellphone use or reading or sending text or e-mail messages while driving.
  • A higher percentage of 25- to 44-year-old men and women reported talking on a cellphone while driving than those ages 55-64.
  • A higher percentage of 18- to 34-year-old men and women reported reading or sending text or e-mail messages while driving than those ages 45-64.