In 1990, 6,366 sexual assaults were reported to law enforcement agencies, a 9.3-percent increase over 1989. Most sexual assaults were either first or second degree. Overall, 41 percent of sexual assaults involved penile penetration or attempted penetration, the definition of rape used in the report. The average age of single-offender rape victims was 18 years, and 96 percent of all rapes involved single offenders; 76 percent of victims were white, and 22 percent were black. Of all single-offender rapes, 59 percent occurred in either the victim's or the offender's home. These rapes tended to occur at night between 8:00 p.m. and 4:00 a.m. Nine percent of single-offender rapes involved the use of a dangerous weapon, and 26 percent of victims reported some physical injury. Most rapes were perpetrated by someone known to the victim. Offenders were arrested in 59 percent of single-offender rape cases. The average age of nonrape sexual assault victims was 14 years, and 97 percent of these assaults involved single offenders. Fifty-six percent of single-offender nonrape assaults occurred in either the victim's or the offender's home, nonrape assaults tended to occur between noon and midnight, 1 percent of assaults involved the use of a dangerous weapon, and 7 to 8 percent of victims reported some physical injury. The majority of nonrape assaults were perpetrated by someone known to the victim. Fifty-three percent of offenders in single-offender nonrape assaults were arrested. Appendixes contain Wisconsin's sexual assault statutes and the sexual assault data collection form. Tables and figures