The bar chart illustrates the number of US households (in millions) classified by annual income categories for the years 2007, 2011, and 2015.
Overall, there is a clear trend towards a larger number of households earning higher incomes over time. In 2007, households earning less than $25,000 accounted for the largest group, slightly above 25 million. However, this number gradually decreased in 2011 and 2015, dropping below 25 million in the latter year. Meanwhile, households with an income between $50,000 and $74,999, as well as those earning $75,000 to $99,999, remained fairly stable across the three years, hovering around 20 to 25 million households.
Notably, the most significant change was in households earning $100,000 or more. This category grew significantly over the years, with the number of households rising from around 20 million in 2007 to nearly 30 million by 2015. Conversely, the middle-income categories, such as those earning $25,000 to $49,999, showed a slight decline in numbers.
In conclusion, the data indicates that while lower-income households decreased over time, the number of high-income households rose sharply, suggesting an increasing wealth divide or income polarization in the US during this period.