Just a few years after a historic run-up in the price of food—grocery costs in the U.S. have been on a steady decline in the U.S. for most of this year.

There are plenty of factors contributing to that, but here’s a big one: oil. Not only is energy a big part of the cost of producing food, but oil is also a big part of the cost of producing many fertilizers. On top of that, cheap crude drives down demand for biofuels, further driving down crop prices.

It turns out years of sinking oil prices have been good for more than just road trips. Shoppers, rejoice.

For more on the energy industry, watch this Fortune video:

A version of this article appears in the November 1, 2016 issue of Fortune with the headline “The Many Effects of Oil’s Big Bust.”