Jobs numbers released on Friday were unsurprisingly good. The country added 228,000 jobs last month, with hourly earnings up slightly. The unemployment rate stayed at 4.1 percent, the lowest figure since December 2000 — at the tail end of the 1990s economic boom. It’s a figure that’s better than five out of six months since 1948.

Normally, one would think that the sitting American president would be enjoying record popularity as a result of those numbers. President Trump, as you are no doubt aware, is not.

Since 1948, the earliest point for which numbers are available, the relationship between presidential approval ratings and unemployment rates is a bit trickier than you might expect. Comparing Gallup’s weekly averages to the unemployment rates each month rounded to the nearest half-point, we see that there’s a broad range of approval ratings that correlate to each unemployment number. For unemployment numbers around 4 percent, for example, presidential approval has been as high as 79 percent and as low as 35 percent.

How to read this: As you move from left-to-right, unemployment is declining. From bottom-to-top, presidents are getting more popular.

And look at that 3 percent number! Harry Truman presided over very low unemployment after World War II — but also was awfully unpopular.

So let’s look only at recent presidents. From Jimmy Carter to Barack Obama, the chart above looks like this.

The trend line here is clearer. As unemployment drops, average approval ratings increase.

That’s Carter to Obama. Now, let’s overlay Trump.

Not only is Trump well-below average — even dropping below the average at 4 percent! — he’s seen his approval rating go down along with the unemployment rate! In other words, as unemployment has dropped over the course of the year, so, too, has Trump’s approval rating.

An interesting detail here is that Trump’s approval rating from members of his own party is about in line with ratings of past presidents — except that as unemployment drops, approval from his own party has dropped, too.

There are reasons for this. Unemployment has slipped over the course of the year, but the economy was already doing pretty well when Trump came into office. At the same time, Trump grew less popular, as is common for first-year presidents. So many Americans probably didn’t feel much improvement to the economy even as they grew more skeptical of Trump.

Trump also has stronger opposition from the opposing party than other modern presidents. Obama’s approval ratings sank as Republicans grew to dislike him vehemently; Democrats always looked at Trump that way.

Regardless, past presidents have enjoyed higher approval from the opposition as the unemployment rate has fallen. Trump started low with Democrats — and slipped lower.

The question that arises, then: What happens if the economy tanks?