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What will you have for lunch today?

Chances are pretty good that many of you answered “a peanut butter and jelly sandwich.” That’s because peanut butter is in 90 percent of American houses. According to one report, most American kids will eat an average of 1,500 peanut butter sandwiches by the time they graduate from high school.

But this regular in lunchboxes and school cafeterias may get rarer because the price of peanuts — and therefore the price of peanut butter — is going way up.

An especially hot summer in states that grow lots of peanuts, including Georgia, Texas and Alabama, has meant there are far fewer nuts to harvest this year. When there’s less of something to sell, that often means prices go up. (That’s called the law of supply and demand.) So last year a ton (2,000 pounds) of peanuts sold for $450. The price has more than doubled to almost $1,200 today.

Some peanut butter companies plan to raise the price of a jar by 30 to 40 percent.