Want to predict how the economy is moving? There’s no better indicator to watch than trash.

In an analysis at Bloomberg (by way of the Washington Post), Michael McDonough and Bob Willis assessed which rail-transported material tracked most closely with broader economic indicators. The least correlation was between carloads of coal. The most? Waste. McDonough and Willis found that the index of how much garbage moved by rail had an 82 percent correlation with the GDP.

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Which makes this graph worrisome.

Image courtesy of Michael McDonough.

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The drop-off in that blue line, indicating waste carloads, mirrors a similar drop-off in 2009 — and you know what happened then. (Or, if you don’t: The economy tanked.)

The American thing to do, then, is have all of your garbage shipped by rail from now on. U-S-A. U-S-A.