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.

  1. How much have US consumer prices risen since 1913?
  2. How much rarer is each step up in earthquake magnitude?

Chart 1 of 2 · Inflation

How much have US consumer prices risen since 1913?

The interactive chart needs JavaScript. The numbers are on the chart's page.

Consumer prices in September 2026 were 34 times their level in January 1913, when the Consumer Price Index begins: what cost $1 then cost about $34 in 2026. They were 2 times their level of January 2000. The index tracks what a typical basket of goods and services costs city households, with 100 as its 1982–84 average. Prices fell after 1920 and again in the early 1930s. October 2025 is missing because BLS collected no prices that month, during a lapse in federal funding.

Questions to discuss

  1. In one sentence of your own, what does this chart show?
  2. Find the biggest change or difference in the chart. What might explain it?
  3. Who collected these numbers, and how recent are they? What else would you want to know before drawing a conclusion?

Source: U.S. Bureau of Labor Statistics, Consumer Price Index (CPI-U, all items) (Public domain (U.S. government work)) · Data as of Sep 30, 2026

Open the chart and its numbers

Chart 2 of 2 · Earthquakes

How much rarer is each step up in earthquake magnitude?

The interactive chart needs JavaScript. The numbers are on the chart's page.

In 2025 the world recorded 6,428 earthquakes of magnitude 4.5 to 4.9, 1,983 of magnitude 5, 129 of magnitude 6, 15 of magnitude 7 and 1 of magnitude 8 or more. Each step up in magnitude is roughly ten times rarer, and releases about 32 times more energy. Countless smaller quakes go unrecorded worldwide, so the chart starts at 4.5.

How to read this chart

Each bar counts the earthquakes recorded worldwide in one year within a range of magnitudes. The bars start at zero. Each whole step up in magnitude releases about 32 times more energy, so a magnitude 7 quake is far more than one step stronger than a 6.

Questions to discuss

  1. Roughly how many times more common is each band than the one above it?
  2. The biggest bars are hard to compare with the smallest ones on this scale. What other way could you show these numbers?
  3. The chart starts at magnitude 4.5. Why might smaller earthquakes around the world go uncounted?

Source: U.S. Geological Survey, ANSS Comprehensive Earthquake Catalog (ComCat) (Public domain (U.S. government work); source U.S. Geological Survey) · Data as of Dec 31, 2025

Open the chart and its numbers

Teachers: make your own chart assignment, or change this one. Free, no account needed.