15.3 percent http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm 54.4 million http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm 15.3 percent http://www.ntia.doc.gov/legacy/opadhome/mtdpweb/sbfacts.htm 54.4 million