What is the fine-grained topic of the following text: At the freshman level, UCSD reported a 7.9 percent rise of historically underrepresented students for fall 2015, with the largest increase coming from African American high school seniors — up 13.5 percent compared to last year, followed by Mexican American — up 7.1 percent. Only return the topic.
Increase in enrollment of historically underrepresented students at UCSD in 2015