male and 23,777,015 (50.96%) female. In recent years, this population has been increasing slowly but progressively. In the last decade, the increase has been largely through immigration: 4,572,055 Spanish residents are foreigners. These numbers count only citizens and legal immigrants. The health care system must also provide services for thousands of illegal immigrants and for the many tourists who visit Spain each year. Population pyramid Analysis of the population pyramid shows that 20 percent of the total population is under 20 years of age. 24 percent of the total population is 20 to 40 years of age. 31 percent of the total population is 40 to 60 years of age. 25 percent of the total population is at least 60 years old. This structure is typical of a modern demographic regimen, with an evolution toward an aging population and a declining birth rate. This means that Spain has to expect an increase in use of the services that are targeted at older adults. This effect is further exacerbated by a steadily increasing life expectancy. See also National Transplant Organization achieved the highest rate of donors in the world in 2006. Miguel de Cervantes Health Care Centre Social Security in Spain Notes Universal health care Publicly funded health care