A 2011 Government Accountability Office study of non-citizens in U.S. prisons and jails during 2003-2009 found that they had been arrested for a total of 25,064 murders. This study states that it accounts only for "a portion of the total population of criminal aliens who may be incarcerated at the state and local levels," because there "are no reliable population data on criminal aliens incarcerated in all state prison systems and local jails." The figure of 25,064 further understates murders committed by non-citizens, because 41% of all murders in the U.S. go unsolved. This rate is higher for minorities, and in the sanctuary city of Chicago, it was 81% in 2016.