Two million or about 4% of school–age children in the United States are homeschooled. It's a much different story overseas: Sweden is cracking down on homeschoolers; Spain doesn't allow it in any case, even if a child is home–bound by illness; it is banned in Brazil; the Netherlands only allows it under exceptional circumstances; Austria allows it, but administers annual achievement tests; and France has a monitoring system that Britain may also adopt.
http://thedrvoice.wordpress.com/2010/12/15/u–s–a–refuge–for–homeschoolers–for–now/