Growth in enrollment and number of schools

The network of Gulen charter schools is expanding rapidly, particularly the Harmony network in Texas, the Concept Schools network in the Midwest, and the Magnolia network in California.
All enrollment numbers used in the graphs below are from the National Center for Education Statistics (NCES). 

Note: The 2000-01 enrollment number of "0" given by NCES for Horizon Science Academy Cleveland is almost certainly erroneous, since the 1999-00 and 2001-02 enrollments were 194 and 352, respectively.  For this reason we noted on the graph that the 2000-01 total enrollment for the Horizon Science Academy schools has missing data. No confirmation of this could be found on the website of the Ohio Department of Education.