Increasing food production to satisfy food requirements is likely to exacerbate pressure on natural resources, such as land and water, and will require sustainable productivity gains. Measured in terms of constant prices (average 2004-2006 United States dollars), the food produced in the region increased in value from $736 billion in 1990 to $1,351 billion in 2013, an 84 per cent increase. The undernourishment indicator measures only food deprivation in terms of calories ingested.