FACTBOX: DNA exonerations in the United States

(Reuters) - Following are some facts and figures about DNA exonerations in the United States.

-- There have been 218 post-conviction DNA exonerations in the United States. Of these 156 have occurred since 2000.

-- The racial breakdown of those exonerated is as follows: 134 African Americans; 59 Caucasians; 19 Latinos; 1 Asian American and 5 whose race is unknown.

-- Exonerations have occurred in 32 states. Dallas County is the leading local jurisdiction with 17.

-- The Dallas District Attorney's Office says it has reviewed 196 defendants in 283 cases.

-- Mistaken identification testimony was a factor in 77 percent DNA exonerations in the United States, the leading cause of wrongful convictions.

-- Lab error and poor forensic techniques have contributed to 65 percent of wrongful convictions.

-- Sixteen of the people exonerated had been sentenced to death and spent time on death row.

-- No court has found that any of the over 1,100 people executed in the United States over the past three decades was put to death for a crime they did not commit. But many observers and analysts say the sheer number of DNA exonerations point to the possibility that this has happened.

-- Only 25 of America's 50 states have legislation that requires the preservation of crime scene evidence.

Sources: Innocence Project; Dallas County District Attorney's Office; Reuters

(Compiled by Ed Stoddard in Dallas)