There were 149 people exonerated in the United States last year after being wrongly convicted of crimes. More than a third of the people exonerated were convicted of murder, says a report released Wednesday by the National Registry of Exonerations, a project of the University of Michigan Law School and the Northwestern University School of Law. All of the people exonerated last year ... had served an average of more than 14 years in prison. Five of the people who were exonerated had been sentenced to death. All told, the National Registry says it has logged 1,733 exonerations in the country since 1989. "Not long ago, any exoneration we heard about was major news," the report stated. "Now it's a familiar story. We average nearly three exonerations a week, and most get little attention." There are also more exonerations in cases involving false confessions or guilty pleas than there used to be. In four of 10 exonerations last year, the people had pleaded guilty, largely in cases involving charges of drug possession. About a third of all exonerations last year involved these drug possession cases. A remarkable number of these cases occurred in just one place: Harris County, Tex., home to Houston. The registry's report described how the Harris County District Attorney's office had investigated cases after noticing a number of people who pleaded guilty to possessing illegal drugs, only for a crime lab - sometimes months or years later - to reveal that the materials these people had were not drugs after all.