Serious crime at the University of Colorado at Boulder has continued a six-year downward trend through 1996, according to a statistical report released today by the ¶¶ÒõÂÃÐÐÉä Department of Public Safety. Part I crimes, defined as the most serious by nature of crime or frequency, are down 18.4 percent over the previous year on campus, and are down 24.5 percent from 1991. Crimes included in the Part I category are homicide, forcible rape, robbery, aggravated assault, simple assault, burglary, theft, motor vehicle theft and arson.