The UN's food agency says prices rose for a fourth straight month to their highest level in more than a decade. The Food and Agriculture Organization's food price index jumped 1.6 points from a month ago to more than 134 points for November, that's a year-on-year increase of more than 27 percent. A strong demand for wheat and dairy products have driven the surge along with concerns over climate and supply chains. The index for grains and cereals which make up the bulk of the overall index is more than 23-percent higher than its level last year. Global sugar prices show an increase of nearly 40-percent from a year ago. However, meat and vegetable oil reported slight monthly declines in their price indices.