Chart assignment
Charts to read and discuss
Read each chart, then answer its questions. Every chart shows its source and date; open it for a table of the numbers and the data to download.
Chart 1 of 2 · Income tax
How many federal income tax returns are filed each year?
The interactive chart needs JavaScript. The numbers are on the chart's page.
About 153 million individual income tax returns were filed for tax year 2023, up from 119 million for 2001. The jump to 157 million for 2020 came as many people with little or no income filed to claim pandemic stimulus payments they had missed; returns filed only to get a stimulus payment in 2008 aren't counted. These counts leave out returns of people claimed as someone's dependent, and are IRS estimates from a sample of returns. One return can cover a married couple filing jointly, so returns are not the same as people.
Questions to discuss
- In one sentence of your own, what does this chart show?
- Find the biggest change or difference in the chart. What might explain it?
- Who collected these numbers, and how recent are they? What else would you want to know before drawing a conclusion?
Source: IRS Statistics of Income, Table 4.1 (individual returns by income percentile) (Public domain (U.S. government work)) · Data as of Dec 31, 2023
Open the chart and its numbersChart 2 of 2 · World
How has the world's population grown since 1960?
The interactive chart needs JavaScript. The numbers are on the chart's page.
The world had 8.22 billion people in 2025, about 2.7 times the 3.02 billion of 1960. It passed 8 billion in 2023. Figures are mid-year estimates from the United Nations, which revises them as new censuses come in.
How to read this chart
Each point is the number of people alive in the world in the middle of that year, estimated by the United Nations. The axis starts at zero, so the height of the line shows the true size. Look at how steep the line is to see how fast the population grew.
Questions to discuss
- Judging from the chart, about how many years did it take the world to add its most recent billion people?
- Is the line getting steeper or flatter in recent years? What does that tell you about the growth rate?
- These numbers are estimates that the UN revises. Why is it hard to count every person on Earth?
Source: World Bank, World Development Indicators: Population, total (CC BY 4.0 (credit the World Bank)) · Data as of Dec 31, 2025
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