With more than a million students now enrolled in public charter schools, and with long waiting lists to boot, we know that the charter school movement is succeeding in offering families new hopes and new choices. But chartering is also beginning to work at scale, which strengthens the chances that it can be a force for broader system change. The impact of charter schools' growing "market share" may be minimized, however, because educators and policy analysts usually think of it in terms of still-modest national numbers (only 2% of all public school students) or the somewhat larger state numbers (where Arizona leads the pack, with 8% in 2005-06). What's often neglected is the growing market share of charters in an increasing number of individual communities. The National Alliance for Public Charter Schools has looked around the country to find the highest local proportions of students enrolled in public charter schools during the 2005-2006 school year. The table below shows the results. Due to numerous ties, there are actually 19 communities that made the 2006 "Top 10."