ROME, ITALY — The United Nations’ Food and Agriculture Organization’s (FAO) Cereal Price Index inched up in September but is still 14.6% below its value a year ago.

The index, which tracks monthly changes in international prices, averaged 126.3 points in September, up 1.3 points from August but 21.6 points below its value a year ago.

The monthly increase was led by a 5.3% increase in international coarse grain prices. Corn (maize) prices increased by 7% in September due to strong demand for Brazil’s supplies, slower farmer selling in Argentina and increased barge freight rates due to low water levels on the Mississippi River in the United States.

International wheat prices continued to drop, falling by 1.6% month-on-month, underpinned by ample supplies in Russia, where production prospects were lifted in September.

The FAO All Rice Price Index edged slightly down by 0.5% month-on-month in September, while remaining as much as 27.8% above its year-earlier value.

The FAO Vegetable Oil Price Index averaged 120.9 points in September, down 5 points (3.9%) from August, marking the second consecutive monthly decline.

The fall in the index was driven by lower world prices across palm, sunflower, soy and rapeseed oils. International palm oil prices continued to decrease in September.