According to the last census that was taken in the year 2005, the population of the entire Madrid (suburbs and the urban areas included) was said to be 5.84 million with the city population being 3.5 million while the urban area population was about 5.5 million. Madrid covers an area of about 234 sq miles or approximately 607 square km. Reserchers have observed that the city's population has risen drastically in the past few years owing largely to immigration-both international as well as domestic. Many believe that this phenomena started taking place after Madrid was coined its new status as Spain's national capital. The current population numbers bear a stark contrast to those during the 1970's, a time when Madrid was experiencing a strong growth slump. Researched data shows that between the years 2001-05 the population increased by approximately 271,856.