That same publication that quoted those numbers said this "Sixty percent of black girls have experienced sexual abuse
at the hands of black men before reaching the age of 18, according to an ongoing study conducted by
Black Women’s Blueprint." They provided no data at all, just direct you to the site.
This is what I've been able to find in the site.
BWB launches
Critical Participatory Action Research using a survey developed and led by survivors of rape/sexual assault to gauge the incidences of sexual assault against Black women in their own communities. The survey found that 60% of Black Women in the U.S. reported experiencing sexual assault, and many before the age of 18 according to initial findings from a survey still ongoing by BWB. Further, we found that Black communities have a host of innovative ideas for supporting survivors, for primary prevention and for grassroots accountability measures.
See what they turned into. Let's not even address the validity of this survey (I'm still looking for more information).
edit: This seems to be the sample size
"Nationally, more than
300 women were surveyed in the study, and the organization hopes to survey a total of 700 women by March 2012. The group will announce its full findings at that time."
and this was the "
survey"