World hunger has declined by 21% since 1990-1992.

ROME — The incidence of hunger worldwide has declined to 795 million people in 2015, down 21% from over 1 billion in 1990-92, according to a report by the Food and Agriculture Organization of the United Nations.

In Its annual hunger report, “The State of Food Insecurity in the World 2015” (SOFI 2015), the F.A.O. said the progress has been made despite challenging conditions and global population growth adding an additional 1.9 billion mouths to feed since 1990.

The prevalence in developing regions of undernourishment, defined as the proportion of people unable to consume enough food for a healthy life, fell to 12.9% in 2015 from 23.3% in the early 1990s, the F.A.O. said.

The reduction in the prevalence of hunger was not as great as the 50% cut sought for 2015 in the Millennium Development Goal targets established in 1996. The F.A.O. said this target was achieved in 72 of 129 countries. A more ambitious goal, cutting in half the absolute number of undernourished people was reached in 29 countries.

“The near-achievement of the M.D.G. hunger targets shows us that we can indeed eliminate the scourge of hunger in our lifetime,” said Jose Garziano da Silva, F.A.O. director general. “We must be the Zero Hunger generation. That goal should be mainstreamed into all policy interventions and at the heart of the new sustainable development agenda to be established this year.”

Ertharin Cousin, executive director of the World Food Program, added, “Men, women and children need nutritious food every day to have any chance of a free and prosperous future. Healthy bodies and minds are fundamental to both individual and economic growth, and that growth must be inclusive for us to make hunger history.”

The F.A.O. said the progress made toward the 2015 food security target was achieved in the face of conditions even more difficult than could have been anticipated in areas of the world accustomed to encountering a range of challenges.

“Extreme weather events, natural disasters, political instability and civil strife have all impeded progress,” the F.A.O. said. “Twenty four African countries currently face food crises, twice as many as in 1990; around one of every five of the world’s undernourished lives in crisis environments characterized by weak governance and acute vulnerability to death and disease.”

The SOFI 2015 report described a change in the nature of problems facing many countries affected by hunger over the past 30 years. While earlier difficulties were characterized by sudden, catastrophic, short-term, acute events that were highly visible, more recent situations have been protracted, because of natural disasters and conflicts, climate change, and financial and price crises often viewed as “exacerbating factors.”

“Hunger rates in countries enduring protracted crises are more than three times higher than elsewhere,” the F.A.O. said. “In 2012 some 366 million people were living in this kind of situation — of whom 129 million were undernourished — 19% of all food-insecure people on the planet.”

The achievements demonstrated that “inclusive economic growth, agricultural investments and social protection, along with political stability make the elimination of hunger possible,” the F.A.O. said, adding that “the political will to make hunger eradication a paramount development objective has fostered progress.”

While Sub-Saharan Africa has the highest prevalence of undernourishment in the world, at 23.2%, the F.A.O. said African nations that invested more in improving agricultural productivity and basic infrastructure achieved their Millennial Development Goal targets. The best progress was in West Africa.

In Latin America and the Caribbean, the proportion of hungry people has dropped to 5.5% from 14.7% in 1990.

“A strong commitment to hunger reduction was translated into substantial social protection programs which, coupled with strong economic growth, drove continent-wide progress,” the F.A.O. said.

Progress was more erratic in Asia. Countries in eastern and Southeast Asia achieved steady and rapid reduction in both malnourishment indicators, progress attributed to investment in water and sanitation infrastructure as well as favorable economic prospects.

“In southern Asia, the prevalence of undernourishment has declined modestly, to 15.7% from 23.9%, but much greater progress was made in reducing underweight among young children,” the F.A.O. said. “Severe food insecurity is close to being eradicated in North Africa, with the prevalence of undernourishment below 5%, while dietary quality is of growing concern in the region, where there is a rising prevalence of overweight and obesity.”

The F.A.O. credited improved agricultural productivity, especially by small and family farmers, as a major contributor to progress toward hunger reduction. Economic growth and the expansion of social safety nets also were credited.