The number of U.S. convicts imprisoned with death sentences dropped in 2003 to its lowest level in 30 years, helping to provoke the third straight annual decline in the nation's death row population and signaling the continuation of a slow trend away from state- and federally ordered executions, according to data released yesterday by the Justice Department's Bureau of Justice Statistics.

The data stirred activists to speculate that support for the death penalty is dropping among jury panels, which in many states now are the only groups eligible to impose it. Only 144 new inmates incarcerated in 2003 were sentenced to execution, well below an annual average of 297 between 1994 and 2000, the bureau's report stated.

The number of executions that were carried out also dropped, from 71 in 2002 to 65 in 2003, while the average length of time between death row sentencings and executions continued to grow. More than 40 percent of those on death row are now imprisoned in three states -- California, Texas and Florida -- while more than two-thirds of the executions were carried out in Texas, Oklahoma and North Carolina.

The Justice Department -- led in recent years by an attorney general who strongly supports the death penalty -- did not return a phone call seeking comment about the data. But Robin M. Maher, director of the American Bar Association's Death Penalty Representation Project, said, "The declining figures probably indicate a loss of confidence in the fairness and reliability of the death penalty."

Maher said her group has noticed "that juries overall . . . seem more cautious about imposing a death sentence," perhaps because of highly publicized recent cases in which police and judicial errors have contributed to death sentences for convicts who were later exonerated through DNA testing or judicial reviews.

According to the Death Penalty Information Center, a group critical of the sanction, 117 death row inmates have been exonerated in the past 30 years, including 21 in Florida and 18 in Illinois. In 2003, outgoing Illinois Gov. George H. Ryan commuted the sentences of every death row inmate, citing what he described as a concern about potential errors.

Ryan's decision accounted for about 60 percent of the 2003 decrease in the number of inmates on death row. But his actions were complemented that year by legislation enacted in six of the 38 states that allow the death penalty to restrain or exclude its application with defendants who are mentally retarded, and legislation imposed by two other states -- Nevada and Idaho -- restricting the authority of judges to impose the death penalty without the support of juries.

Charles Hobson, a lawyer with the Sacramento-based Criminal Justice Legal Foundation, which supports crime victims, expressed skepticism about the data's significance. He noted that no state acted in 2003 to bar the death penalty altogether and said that making year-to-year comparisons is difficult because the number of such sentences is routinely small.

"The numbers are decreasing, but this is almost entirely explained by what was done in Illinois," Hobson said. Claims of judicial errors are overstated, and "concluding anything with respect to [the opinions of] juries is purely guesswork," he added.

Two states -- Texas and Colorado -- actually expanded their authority to impose the death penalty in 2003. Texas alone has accounted for more than a third of the 885 inmate executions since 1977, according to the bureau's report.

An officer checks death row inmates' cells at San Quentin in California. The nation's death row population declined for the third straight year.