At least 21 people were killed at school during the 2004-05 academic year, a slight increase from the year before, the government reported Sunday.

The study by the Bureau of Justice Statistics does not include data from fatal shootings in Wisconsin, Colorado and Pennsylvania this fall. In Pennsylvania, five Amish girls were killed in a one-room schoolhouse by a milk truck driver who then turned the gun on himself.

Overall, fewer students reported being the victims of violent crime at school or school-sponsored events in 2004-2005, the study by the Justice Department agency show. Additionally, school-age children remain far more likely to be assaulted, raped and robbed off school grounds.

The study looked at violent crime against students over several periods of time.

The 21 killings at school-related events, between July 2004 and June 2005, targeted victims between age 5 and 18, said Katrina Baum, co-author of the 2006 Indicators of School Crime and Safety. Over the previous year, 19 people were killed.

It was not immediately clear whether all the victims were students. Still, the preliminary data indicates that students were about 50 times more likely in the 2003-04 school year to be killed away from school than at school, the report shows.

The number of deadly shootings has risen and fallen over the past 15 years. Overall school violence has shown a declining trend, although it has increased lately.

The study notes that four of every 1,000 students in 2004 reported being the victim of violent crimes — compared with six of every 1,000 in 2003. Researchers polled students between 12 and 18 for that part of the survey, co-written by the Education Department's National Center for Education Statistics.

Younger students were found to be more likely crime victims — including those injured by bullies, the report showed. Last year, 28 percent of students polled said they had been bullied.

Also in 2005, 24 percent of students questioned said that gangs were at their schools — up 3 percent from 2003. The rates of fights, drinking alcoholic beverages, and weapons found at schools remained at 2003 levels, the report noted.