The chart below shows the number of households in the US by their annual income in 2007, 2011 and 2015. Summarize the information by selecting and reporting

The box chart illustrates the

number

of American

households

by their yearly income in a 4-year interval between 2007 to 2015.

Overall

, the

number

of most

groups

showed some degree of fluctuations throughout the years, with the notable exception of the middle and the second highest net worth

groups

. In 2007, the

number

of middle-income and middle-high-income

groups

was around 20

million

and 15

million

, respectively. The

number

remains relatively unchanged in the following year and the year after, particularly in the middle-income group.

However

, the second-highest income

households

showed a small increase to 15

million

in 2015, with a slight dip in between.

On the contrary

, a fluctuating trend was observed in the lowest, the low-middle and the high-income

households

. There was a dip in the

number

of high-income

households

in 2011 before experiencing a resurgence to around 35

million

in 2015.

However

, the opposite occurred in the other two

groups

, which experienced an increase in the

households

instead

.