Since the 1960's, the population in the United States has risen at a rate of about 2 million people per year. This population increase has been felt more in the inner cities than in the suburbs. This rise in population has been the result of both the continuous reproduction of its people and the longer life span of humans due to technological advances within our society. .
The reasons behind the increase in population being contained almost entirely in the urban areas vary. One possible explanation of this trend is that it develops as a result of the economic situation in the United States. Most Americans cannot afford to travel long distances to get to their work places and are therefore required to live near their work. On top of that, most businesses that pay enough money to live comfortably will be placed in a higher population area. This is done in order to maintain a constant work force to maintain the company. .
Higher income families can afford to commute longer distances to work. As more families are able to afford the commute, neighborhoods become larger. Once an area builds up enough population, it will then be subject to larger businesses moving into the area. At this point, lower income families are able to move into the area and accept jobs at these new businesses. Over the course of a decade or two, the once sought-out neighborhood is now just another middle-class subdivision. This process will repeat itself over and over again until most all of the "rural" areas are gone. The end result of the population increase will be that the big cities will cover a larger land mass and most of the small cities throughout the United States will be grown over by the expanding.