A 17 percent drop in overseas travellers to the United States since the Sept. 11 attacks has cost the country more than $15 billion in lost taxes and nearly 200,000 jobs, a study showed on Tuesday.

Since the Sept. 11 attacks, the United States has tightened security measures and toughened its visa and entry requirements. As a result, the country was ranked as the world's most unfriendly to visitors in a survey conducted last year of travelers from 16 nations.

"Our economic security is suffering from a drastic decline in overseas travelers and we are missing an extraordinary opportunity to strengthen America's image around the globe," said Stevan Porter, president of Intercontinental Hotels Group and chairman of the association's Discover America Partnership. "We are in the midst of a travel crisis."

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The study released on Tuesday by the Travel Industry Association said the U.S. market share of the $6 trillion worldwide travel market had dropped to about 6.1 percent in 2006, from about 7.5 percent in 2000. Since Sept. 11, overseas travel to the United States has dropped by 17 percent.

The study, which looked at the economic ripple effect over time, said the drop resulted in 194,000 lost jobs, $25.9 billion in lost payroll and $15.6 billion in lost taxes to federal, state and local governments.

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