You gave them the choice of yes or no, whereas, as of 2005, you gave them the choice of suspected gang activity. Would that lead to an indication upwards? If you were given the choice of defining, “Is this a gang-related homicide, Mr. Police Force”, it's easier to say “I suspect it to be so”, than to say “I definitely know it is”. So I guess it would lead to a bit of a spike or rise, as of 2005, when it came in.
On November 22nd, 2006. See this statement in context.