A new study by Washington DC-based think tank, Urban Institute reveals the average number of years prisoners spend in jail has increased. According to the Marshall Project, between 2000 and 2014, the average time served rose by around 37 percent. And the 10 percent who have been in prison for the longest period, mostly serving sentences for violent crimes, saw their jail time by go up by 42 percent. According to the report, four out of every 10 people in jail are Black. And the number rises to almost five Black prisoners out of every 10 for those serving the top 10 percent of long term sentences. over 5 million children have had at least one parent in prison at some point in their lives.