title: Charter schools in the United States
context: As of 2016-2017 there were an estimated 6,900 public charter schools in 42 states and the District of Columbia (2016–17) with approximately 3.1 million students, a sixfold increase in enrollment over the past 15 years.[3] In 2015 alone, more than 400 new charter schools opened while 270 schools closed due to low enrollment, lack of finances or low performance.[4] Waiting lists grew from an average of 233 in 2009 to 277 in 2012,[5] with places allocated by a lottery.[6] They educate the majority of children in New Orleans Public Schools.[7] Some charter schools provide a specialized curriculum (for example in arts, mathematics, or vocational training). Charter schools are attended by choice.[8]
question: How many charter schools are there in the U.S.?
answers: an estimated 6,900 public charter schools in 42 states and the District of Columbia