Final answer:
The correct statement regarding current U.S. population trends is that the nation's overall growth rate has been decreasing over the past three decades. The aging population is increasing due to higher life expectancy, while the birth rate is declining.
Step-by-step explanation:
Looking at the current population trends in the United States, the statement that the nation's overall growth rate has been decreasing over the past three decades is correct. This trend reflects a variety of factors including declining birthrates, an aging population, and the rising costs associated with raising a child in urban settings. The life expectancy in the U.S. has been generally increasing, leading to a higher proportion of seniors in the population and thus a phenomenon known as 'the graying of America.' While the number of young people has decreased, the proportion of the population aged 65 and older has more than tripled in the past century. Moreover, the U.S. Census Bureau projects that most of the population growth in the near future will be among minority groups, particularly Hispanics, and not from the baby boomers who are moving into the older age categories.