The frequent occurrences of gun killings were a serious threat to the lives of U.S. citizens. According to the U.S. Center for Disease Control and Prevention, 1.35 million high school students in 2007 were either threatened or injured with a weapon at least once on school property (United Press International, October 3, 2008). Young people represent an expanding proportion of all shooting victims, from 13 percent in 2002 to more than 21 percent in 2007. According to a Harvard University survey of high school students in 2006, a fifth of the 1,200 questioned in schools across Boston had witnessed a shooting. More than 40 percent believed it was easy to get a gun, and 28 percent said they did not feel safe on the bus or train (The Boston Globe, September 18, 2008). In the 2007-08 school year, a record 34 Chicago Public School students were killed (The Chicago Tribune, April 2, 2008). Within a week from February 7, 2008, the United States had seven shooting incidents, leading to 23 deaths and dozens of injuries. On March 27, 2008, five people in Georgia and Kentucky were shot dead (The Associated Press, March 27, 2008). On the night of April 18, nine shootings were reported in a period of less than two hours in Chicago (The Chicago Tribune, April 21, 2008). In November, Baltimore had 31 shootings (The Baltimore Sun, December 2, 2008). On December 24, 2008, a man dressed in a Santa costume shot at a Christmas Eve party at his ex-parents-in-law's house, causing eight deaths, three injuries and three missing persons (The China Press, December 26, 2008).