No, they only take into account those that are reported to law enforcement.
“According to the 1999 United States National Crime Victimization Survey, only 39% of rapes and sexual assaults were reported to law enforcement officials.”
“According to United States Department of Justice document Criminal Victimization in the United States, there were overall 191,670 victims of rape or sexual assault reported in 2005.[16] Only 16% of rapes and sexual assaults are reported to the police (Rape in America: A Report to the Nation. 1992).[17] 1 of 6 U.S. women has experienced an attempted or completed rape. (according to Colorado Coalition Against Sexual Assault)[18]”
Wikipedia
To show the level of underreporting against reported statistics:
“24% (1 in 4) of Colorado women and 6% (1 in 17) Colorado men have experienced a completed or attempted sexual assault in their lifetime. This equates to over 11,000 women and men each year experiencing a sexual assault in Colorado. (Sexual Assault in Colorado: Results of a 1998 Statewide Survey. 1998. Colorado Department of Public Health and Environment and Colorado Coalition Against Sexual Assault)
1,794 rapes were reported to Colorado law enforcement in 1997. If compared to the 1998 Statewide Survey, these reports constitute only 16% of sexual assaults.”
Colorado Coalition Against Sexual Assault