The bar chart illustrates the number of households in the US based on their annual income for three different years: 2007, 2011, and 2015.
Overall, while the numbers of middle-class and upper-middle-class individuals remained almost steady throughout the given years, the numbers of lower-class, lower-middle-class, and upper-class individuals fluctuated in various ways.
It can be observed that the number of people earning between 50 and 75 thousand dollars stayed roughly the same across all three years, with their figures slightly exceeding 20 million. Similarly, the number of individuals in the upper-middle class, earning between 75 and 100 thousand dollars, did not change significantly over time, although their figures were slightly less stable than those of the middle class.
On the other hand, the number of lower-class individuals rose from just over 25 million to just under 30 million between 2007 and 2011, then slightly decreased to around 27 million in 2015. A similar pattern was observed for the lower-middle class, with an increase between 2007 and 2011 followed by a decrease to 2015, fluctuating near 27 million households. However, the number of individuals with incomes exceeding 100 thousand dollars decreased from 2007 to 2011 but then increased to over 30 million after 2011.