If you are feeling down about the most recent report on inflation, we may have just what the doctor ordered.

Prescription drug prices just recorded their largest annual decline in American history, according to the consumer price index report released by the Department of Labor on Wednesday.

The index for prescription drug prices fell 1.2 percent in September and was down 4.5 percent from a year earlier. In its historical comparison table, the government supplied a wonderfully concise verdict: “S-EVER,” meaning the smallest annual change ever recorded. For a falling price index, that means the biggest decline on record.

As recently as July, the annual decline was 3.1 percent, the steepest since March 1963, when prices fell 3.2 percent. September’s figures have carried us beyond that Kennedy-era comparison and into record territory.

This is a substantial development in a country where expensive medicine has long seemed as permanent a feature of American life as politicians promising to do something about it.