47: Percentage of 100 rampage killings between 1949 and 2000 that were precipitated by loss of job

22: Percentage involving a romantic issue or breakup

96: Percentage of killers who were males

58: Percentage of killers over 25 with a college degree or some college

.01: Percentage of all killings in the U.S. classified as a rampage killing

Source: The New York Times