Even though only about 30 percent of Americans may be holding a valid passport, the number of U.S. travelers visiting Switzerland is on the rise.

According to a tourism data released by the Swiss Federal Office of Statistics recently, the arrivals of Americans in Switzerland increased by 11.5 percent, while the number of nights U.S. tourists spent in Swiss hotels was up 8.9 percent in 2010.

Swiss Statistics said that there has been an unprecedented surge in arrivals of U.S. travelers since the end of 2009 through 2010.

The U.S. again is the third most important foreign market for Switzerland, with more than 1.5 million overnights in Swiss hotels, Alex Herrmann, director of Switzerland Tourism, North America, said.

The region of Central Switzerland, including the city of Lucerne is reportedly the most popular tourist destination for Americans, as the place received a large number of U.S. visitors in 2010, as have the Matterhorn region (17.6 percent) and the city of Basel (17.3 percent).

The Swiss Statistics report said various factors have contributed to the rising trend. Increased air capacity due to the new direct Swiss flights from San Francisco to Zurich and slowly rebounding business travel in the U.S. have helped bring more tourists from the country in to Switzerland, the report stated.