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 · Interest rates
When has the Treasury yield curve been inverted?
The interactive chart needs JavaScript. The numbers are on the chart's page.
The yield curve is inverted when short-term Treasury rates are higher than long-term ones: lending to the government for 2 years pays more a year than lending for 10. On this chart that is anything below zero. In October 2026 the 10-year rate minus the 2-year rate was 0.39 percentage points. Through mid-2026, the longest inversion in these monthly averages lasted 26 months, from July 2022 to August 2024, and the deepest was in March 1980, when the 2-year rate was 2.13 points higher. Inversions have tended to come after the Federal Reserve raised short-term rates quickly, while investors expected rates to fall later. The chart starts in June 1976, when the 2-year rate begins.
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: Federal Reserve Board, H.15 Selected Interest Rates (monthly averages) (Public domain (Federal Reserve Board; cite the Board as the source)) · Data as of Oct 31, 2026
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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