The following statistics reveal the challenges facing the Immigration and Naturalization Service. Information is culled from newspaper articles, the INS and Census Bureau figures:

— In October and November 2001, 7,000 visas were issued to men from countries in which Al Qaeda is known to be active.

— Approximately 115,000 people from Middle Eastern countries live in the United States illegally.

— Saudi Arabians wishing to travel to the United States typically are not interviewed by the State Department. They can obtain visas through travel agents or "drop boxes" near the U.S. consulate offices in their country. Fifteen of the 19 hijackers obtained their visas in Saudi Arabia.

— Each of the 19 hijackers had Social Security numbers, which they obtained legally.

— At any given moment there are approximately 350,000 people who have become illegal immigrants by overstaying their visas.

— INS estimates that 300,000 people who have been ordered deported are still in the country because their deportation orders have not yet been enforced. In many cases, after being ordered deported by a judge, the immigrant simply walks out of the courtroom.

— Between 6 million and 8 million people living in America are dual-citizens.

— Prior to 1965, the average annual number of immigrants and refugees to the United States was about 200,000 people. Since 1990, this number is about 1 million people per year, not including illegal immigrants.

— The INS has a processing backlog of approximately 4.5 million immigration applications.

— The General Accounting Office found that the INS wastes around $100 million per year by not efficiently managing the deportation of criminal immigrants.

— The Department of Justice's Office of the Inspector General did not find any evidence that the INS is capable of locating visa violators still in the country.

— Two weeks after Sept. 11, former INS Commissioner under President Clinton Doris Meissner said at a Carnegie Endowment for International Peace forum that tracking down people who overstay their visas has been "a very, very low priority, and I think it should be a low priority."

— Bush administration commissioner James Ziglar was confirmed for the job in August right before the attack. His only law enforcement experience is serving as the Sergeant-at-Arms for the Senate.