The American Board of Internal Medicine has issued more than 425,000 initial certificates in internal medicine and its subspecialties in the United States and its territories since its founding.[16] From 2001 to 2013, American Board of Internal Medicine certified 91,024 physicians in general internal medicine.[17] From 2001 to 2013, the American Board of Internal Medicine certified more than 10,000 cardiologists and more than 6,400 medical oncologists.[18] More than 140,000 physicians – including more than 8,000 physicians holding certifications that hold certifications which are valid indefinitely — are currently enrolled in the American Board of Internal Medicine's Maintenance of Certification program.