The percentage of women who have experienced sexual assault varies depending on the source and definition of sexual assault. Here are some statistics from various sources:

• One in five women in the United States experienced completed or attempted rape during their lifetime.
• One in four women and about one in 26 men have experienced completed or attempted rape.
• About 14.8% of women in the United States have experienced completed rape in their lifetime, and 2.8% have experienced attempted rape.
• Over 40% of women in the US have encountered sexual violence.
• 90% of adult rape victims are female.

It is important to note that sexual violence is notoriously difficult to measure, and there is no single source of data that provides a complete picture of the crime. Additionally, many cases of sexual assault go unreported, so the actual percentage of women who have experienced sexual assault may be higher than reported.