Why was population growing in the United States?

Population change at the national level stems from natural increase (the difference between births and deaths) and international migration (the movement of people into and out of the United States). So far this decade, natural increase has been the largest source of population growth for the nation

an informal structure in a bureaucracy would be something like so-called "office politics". where there's a formal structure set up for the organization, but then an informal subculture as well that has a way of organizing the bureaucracy further. this can be positive because it sets up an added degree of organization, albeit informal, within the bureaucracy.