Final answer:
The notable shift in the US population has been predominantly from rural to urban areas, with approximately 80% of the population living in metropolitan areas. This urbanization trend has been ongoing since the 1950s due to economic developments and societal changes.
Step-by-step explanation:
Regarding the notable shift in the US population, the data from various sources, including the US Census Bureau, indicate that there has been a trend toward urbanization, which entails a significant population movement from rural areas to urban areas, particularly metropolitan areas. This movement has been consistent since the 1950s when most Americans lived in small towns or rural settings. While migration trends can fluctuate, and there have been discussions about people moving to coastal or mountainous regions at different points in time, the overwhelming trend has been towards urbanization, with about 80% of the US population now living in metropolitan areas, including suburbs.
These shifts can be attributed to a range of factors, including societal and economic transformations. The creation of suburbs in the early 1950s, industrial activities, increased service sector jobs, and the draw of multinational corporations have all contributed to this rural-to-urban shift. Urban populations grow as people seek employment, urban planning becomes crucial, and while income levels tend to increase, family sizes often decrease.