The percentage of new California high school graduates who enroll in the University of California and California State University Systems has dropped from 22 percent in 2007 to less than 18 percent in 2010, according to a report  issued Wednesday night by the Public Policy Institute of California. Further, the enrollment of California high school graduates who have completed courses required for admission to the university systems has dropped from 67 percent to 55 percent. The declines are the apparent result of population growth at a time of deep budget cuts that have limited enrollment and led to tuition increases at many of the state's universities. The enrollment drop has been steepest among black students. While there has been a slight increase in the enrollment rates at community colleges, that has not offset the other declines. The report says that it appears that more California high school graduates than in the past are enrolling at four-year institutions outside the state.