Criminal Immigrants Seen as Biggest Threat to US

There are a number of possible threats that the U.S. might face. How likely do you think the following will be a major threat to the U.S. in the next five years?
(Extremely / Very likely listed)

A large number of illegal immigrants come into the country	55%
A significant loss of jobs to foreign countries	52%
A significant natural disaster destroys large areas of a major city	43%
Energy needs significantly exceed energy supplies	40%
Significant trade imbalances lead to foreign ownership of the country’s debts and property	35%
Terrorists launch a number of attacks against airplanes	26%
The national government becomes unable to borrow money due to a huge debt load	26%
The country is attacked with biological weapons	24%
A significant rise in the level of the oceans	23%
Major riots by groups within this country	20%
A major world war occurs involving most industrialized nations	15%
The banking system experiences a major financial collapse	14%
A city within the country is attacked with a nuclear weapon	14%
A large scale avian flu epidemic	11%
A major stock market crash occurs	11%

Source: Harris Interactive
Methodology: Online interviews with 1,508 American adults, conducted from Jan. 5 to Jan. 12, 2007. Margin of error is 3 per cent.