this is a NYTims article basically indicating; while death penalty sentences are on the decline, new convictions are only in local county situations. Most convictions are not where expected. Seems a local county DA's office, on the path to get re elected, can still prove they are tough on other people's crimes by having a death convictions pending.

references:
a recent NYTimes article:
http://www.nytimes.com/2016/08/28/magazine/where-the-death-penalty-still-lives.html?hp&action=click&pgtype=Homepage&clickSource=story-heading&module=photo-spot-region&region=top-news&WT.nav=top-news&_r=0

associated research paper seems to be using 2004-2009 data
http://www.bu.edu/law/journals-archive/bulr/documents/smith_001.pdf