The National Registry of Exonerations just reported that in 2015, a record number of 149 people were exonerated in the US. Of these, over 50 were homicide cases.
On average, these exonerees had served 15 years for crimes they did not commit.
This is a good start, but not nearly enough. There are still far too many — including Lorenzo — who remain wrongfully incarcerated.
An article by Mother Jones delves deeper into these statistics, and the entire report can be found here.