WASHINGTON - The state of US economy remains the top concern for Americans in 2013, as a Gallup poll released on Tuesday shows that 68 percent of them worry about the economy "a great deal".

In fact, economy has ranked as the top public concern for Americans in this annual Gallup poll each year since 2008. Prior to that, healthcare was the top-ranking concern.

Economy is followed by federal spending/the deficit (61 percent), healthcare (59 percent), and gas prices (55 percent) as other top concerns for Americans in 2013, the poll finds.

Unemployment has slid for the third year in a row in the list of top concerns for Americans, including a 5-point drop this year to 50 percent. Equally 50 percent of Americans worry a great deal about Social Security, according to the poll conducted March 7-10 on 1,022 Americans.

Other major concerns for Americans include the size and power of the federal government (49 percent), crime and violence (47 percent), hunger and homelessness (43 percent), and illegal immigration (37 percent).

The biggest shift in worry this year is a 13-point drop, from 48 percent to 35 percent, in the percentage of Americans who worry about energy availability and affordability.

The percentage of Americans who worry about gas prices declined by 10 points, from 65 percent last year to 55 percent, the poll shows.

Meanwhile, Americans' concern about drug use dipped 6 points this year to 36 percent, which is the lowest record in the poll since 2001.