The Houston Independent School District (HISD) is the largest public school system in Texas, and the eighth-largest in the United States. Houston ISD serves as a community school district for most of the city of Houston and several nearby and insular municipalities in addition to some unincorporated areas. Like most districts in Texas, it is independent of the city of Houston and all other municipal and county jurisdictions. The district has its headquarters in the Hattie Mae White Educational Support Center in Houston. In 2016, the school district was rated "met standards" by the Texas Education Agency. The Brunner Independent School District merged into Houston schools in 1913-1914. Houston ISD was established in 1923 after the Texas Legislature voted to separate the city's schools from the municipal government. In the 1920s, at the time Edison Oberholtzer was superintendent, Hubert L. Mills, the business manager of the district, had immense political power in HISD. He had been in the employment of the district over one decade before Oberholtzer started. By the 1930s the two men were in a power struggle. The number of students in public schools in Houston increased from 5,500 in 1888 to over 8,850 in 1927. In the 1920s, the school district expanded its infrastructure to accommodate a growing number of black students. There were 8,293 students in Houston's schools for black students in the 1924-1925 school year. In 1927, Houston ISD annexed the Harrisburg School District's colored school. The district also built new schools such as the former Jack Yates High School (later Ryan Middle School) and Wheatley High School. The capacity of Houston's secondary schools for black children increased by three times from 1924 to 1929. The original secondary school for blacks was named Colored High School (now Booker T. Washington High School). At the time, the district's three secondary schools for black students had junior high and senior high levels. There were 12,217 students in the black schools in the 1929-1930 school year.