government also runs the Military Health System. In fiscal year 2007, the MHS had a total budget of $39.4 billion and served approximately 9.1 million beneficiaries, including active-duty personnel and their families, and retirees and their families. The MHS includes 133,000 personnel, 86,000 military and 47,000 civilian, working at more than 1,000 locations worldwide, including 70 inpatient facilities and 1,085 medical, dental, and veterans' clinics. One study estimates that about 25 percent of the uninsured in the U.S. are eligible for these programs but remain unenrolled; however, extending coverage to all who are eligible remains a fiscal and political challenge. For everyone else, health insurance must be paid for privately. Some 59% of U.S. residents have access to health care insurance through employers, although this figure is decreasing, and coverages as well as workers' expected contributions vary widely. Those whose employers do not offer health insurance, as well as those who are self-employed or unemployed, must purchase it on their own. Nearly 27 million of the 45 million uninsured U.S. residents worked at least part-time in 2007, and more than a third were in households that earned $50,000 or more per year. Funding Despite the greater role of private business in the US, federal and state agencies are increasingly involved, paying about 45% of the $2.2 trillion the nation spent on medical care in 2004. The U.S. government spends more on healthcare than on Social Security and national defense combined, according to the Brookings Institution. Beyond its direct spending, the US government is also highly involved in healthcare through regulation and legislation. For example, the Health Maintenance Organization Act of 1973 provided grants and loans to subsidize Health Maintenance Organizations and contained provisions to stimulate their popularity. HMOs had been declining before the law; by 2002 there were 500 such plans enrolling 76 million people. The Canadian system has been 69–75% publicly funded, though most services are delivered by private providers, including physicians (although they may derive their revenue primarily from government billings). Although some doctors work on a purely fee-for-service basis (usually family physicians), some family physicians and most specialists are paid through a combination of fee-for-service and fixed contracts with hospitals or health service management organizations. Canada's universal health plans do not cover certain services. Non-cosmetic dental care is covered for children up to age 14 in some provinces. Outpatient prescription drugs are not required to be covered,