Why Percents and Percentage Points Are Cousins, But Not Twins

The distinction between percents and percentage points (or lack thereof) is easily on my list of top 5 pet peeves, so I very much appreciate this comic. This distinction is really important when writing or reading things that have to do with numbers, and the distinction can be shown via a simple example:

Let's say that unemployment is at 10%. (A reasonable assumption nowadays, sadly.) If I were to say that "unemployment decreased by 4 percentage points," this would mean that unemployment is now at 6%. Simple, right? On the other hand, if I were to say that "unemployment decreased by 4 percent," this would mean the following:

10% = 0.1
4% = 0.04
decrease = 4% of 10% = 0.04*0.1 = 0.004
new unemployment = 0.1 - 0.004 = 0.096 = 9.6%

6 percent and 9.6 percent aren't even close to the same thing, so understanding the difference between percents an percentage points is pretty significant. Let's just hope that the people writing about the numbers know how to make this distinction properly as well.